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Help me diagnose- 1996 Cavalier z24 overheating


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Rtodde
Novice

May 27, 2012, 11:56 AM

Post #1 of 20 (4118 views)
post icon Help me diagnose- 1996 Cavalier z24 overheating Sign In

Hey I'm new here just looking for some advice on how to approach fixing my cars overheating issue once and for all, thanks in advanced everyone.

So I'll start by stating that this cavalier has sat unused on and off for a year at a time. Last time I drove it the engine would overheat when driving in traffic and it required I used the heater to force the radiator fan to kick in. Since then I have changed the temp sensor and resolved the issue.

So the fan kicks in once temps go past 90, but it's still overheating! I was driving it yesterday and after some heavy traffic when I engaged the clutch to drive the car would barely move even though the engine would rev, I thought maybe the clutch was burned but after parking a few minutes with the hood open it drove fine again. When I open the coolant reservoir coolant would bubble out quite a bit. Which makes me think it could be the thermostat stuck closed, which I'm going to replace asap.

It's how it affected the driving that confused me, how could a hot motor make it feel like the clutch is slipping? I would go to take off in first and the engine would rev up sluggishly and the car would barely move, switch to second, same thing, also in third.... this is accompanied by a burning smell by the way. Once the car cooled down the clutch felt like it was grabbing great again, is this symptomatic of a heat issue? I looked in the oil and exhaust for signs of a blown head gasket and there is no reason to think that's the problem (oil is normal, and no white smoke from the exhaust ). I checked my coil pack and plugs they look fine.

So besides the thermostat what could this be? Any advice would be greatly appreciated so I can fix this and avoid causing any more damage to my engine. Also I'm tired if driving with my heater on to keep my rad fan on to buy time from it overheating.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 27, 2012, 5:54 PM

Post #2 of 20 (4059 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Running heater doesn't force fans for radiator to come on, A/C does in some but just makes matters worse if fans are not coming on.

Overheating can be but rarely a t-stat that won't open.

* Clogged up or dirty radiator
* Blown head gasket can leak any which way it seals not just mess up oil - they can fail to put combustion gasses into cooling system and will overheat
* Engine revving up and car not going faster with clutch engaged is near always a blown/worn clutch not from overheating engine IMO and generally not intermittent so put that on the growing list of things going wrong

** Overheating for whatever the cause when to the point of boiling bubbles into reservoir is VERY damaging.

There's a long list of reasons for overheating. Initial reason just the beginning and now expect it to need that fixed and whatever other damage likely happened plus a clutch job and think about whether this about 17 year old car is worth the fix vs cutting losses or go for everything but as said doubt all this will be close to cheap to get back to dependable again,

T



Rtodde
Novice

May 27, 2012, 8:29 PM

Post #3 of 20 (4045 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Thankyou for the reply, I'm sure the car will never bee 100% again due to the costs, it's simply not worth it. I don't think it's a clogged radiator since I had it replaced about a year ago, it got in it from overheating I believe, which makes me want to fix it to prevent it happening again. Are there any more specific symptoms I can look for regarding the possible blown head gasket, I checked the oil it's not frothy or white it looks like normal oil, there are no weird smells from the exhaust just the smell of coolant burning after the engine starts overheating in heavy traffic. The clutch slipping is very intermittent, when the car is overheating it feels like it's slipping, when u start her up the next day the clutch grabs great, so could it really be a worn clutch?

I don't know if I mentioned but I took off the coil pack and there was some dirty oil sitting around them but no oil in or around the plugs, it could have been a spill from an oil change. Could that by symptomatic of a blown head gasket?

Again any advice is greatly appreciated, sort of stuck as to whether to drive it into the ground for the next year or spend some money fixing it, it only has 140,000 kms (87,000 miles) so the engine should have some life in it. Could it be a water pump issue?


Oh an about the heater turning on the rad fan, it does work, I don't know why but if the car is parked and I turn it on the fan comes on instantly even if the car is cold. The fan turns on at woo or so degrees but I'd rather my wait. Thinking of wiring it o. Permanently until I fix this overheating issue.

In Reply To



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 28, 2012, 12:40 AM

Post #4 of 20 (4035 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Diagnosing why this overheats can take some work, testing and observations. I don't understand why fan(s) for radiator come on with heat request with a cold engine and think there's a fault somewhere in that fan comes on. Generally they wait till a certain temperature and several will plain come on if selecting any mode that would enable A/C (if equipped) even defrost, which does allow A/C to come on even if colder ambient temps.

Again - many things can cause overheating, water pump might have corroded impeller and not enough flow, thermostat is possible, air in system or combustion gasses would make engine behave as if there wasn't enough antifreeze.

As said, an issue with head gasket or possible head itself with a crack.

This issue with bubbling antifreeze is either really boiling or gasses overpressure system with combustion gasses and would do that as it would exceed pressure rating of system's pressure cap.

If this is doing that you would probably feel (careful where you put your hands) pressure in upper radiator hose build up faster than just expansion of it warming up. Test strips can be used to see if gasses are in cooling system.

AGAIN - head gasket can leak any which way of anything it is sealing not just coolant in oil.

One relatively easy test to start is to see if spark plugs are all the same condition along with other tests.

I suggest you get this whole thing diagnosed professionally. You will not know if head is any good till it is apart and checked out at a machine shop.

Cluch slipping intermittently?! It may just be able better cold but there's a problem there that wont take long till it does nothing. Sometimes a bad motor mount can cause it but clutch can't slip too long before it's gone for any reason. Some folks "ride" a clutch or use it to hold car - say at a stop in traffic or stop sign waiting. traffic light or whatever and that will kill them quickly.

Oil issue could be a spill or other problem - just would need to do some testing, cleaning it up and see if it can be seen. Several reasons for that too.

Alone if not excessive that's another issue of many with this car IMO,

T



Rtodde
Novice

May 28, 2012, 3:51 AM

Post #5 of 20 (4030 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Thanks for helping me understand the possible multitude of issues going on here, I'm going to take your advice and at the very least take it to a mechanic and pay to get a proper diagnosis. Then see if I can fix it myself if it's worth the trouble. I'll be sure to post my findings for anyone else w similar problems. One last question, does engine breaking kill a clutch? I've been driving 4 years in and out of the city daily in a manual car and I ways engine break, usually 3rd and 4th gear.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 28, 2012, 5:38 AM

Post #6 of 20 (4024 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Using engine as a brake or to slow down is effective but now a bit old fashioned. Much older vehicles in mountain conditions (been there done that) brakes can get so hot they cease to work! Spent much time in Rocky Mountains now long ago with loooong stretches of pretty steep driving. There and other places do have places to pull over and let brakes cool off.

They relatively few bucks for professional diagnosis is money well spent as hands on inspection beats a web site for something like this. The tools and experience needed for extensive work isn't practical for many folks for a one time fix for problems you are having as I see it. Other things we can make real good guesses or give some specs or pics on.

The diagnosis of what it will take and cost will help you decide on what to do.

If you do bail out on this car I do suggest if you choose used to have that one professionally checked out so you don't just "jump out of a frying pan into the fire" type thing.

Good luck with whatever you choose to do,

Tom



nickwarner
Veteran / Moderator
nickwarner profile image

May 28, 2012, 4:17 PM

Post #7 of 20 (4009 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

I will second Tom on engine braking. I'm used to driving semis and I always downshift through my gears when in a manual car. What will cause damage is not giving it a blip of throttle to bring engine revs up to match your gear when you do it. Then you stress the clutch. I double clutch my downshifts out of habit but not needed with your car.


Rtodde
Novice

Jun 6, 2012, 3:33 AM

Post #8 of 20 (3954 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Hey everyone I just wanted to quickly update you on what my mechanic said when he saw my car.

Basically besides the various internal causes of overheating he thinks are there, he told me there is an issue in the motor somewhere between the flywheel and the motor, he told me he would have to open it up to really see and thus have to charge me. So all things considered I've decided to get rid of the car and look for a 2000 or so civic with low kms (120,000 or less) good idea?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jun 6, 2012, 6:31 AM

Post #9 of 20 (3948 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

No matter what the reputation of a car is, once a used car it depends a lot on the care along the way and any accidents. Money well spent to get it totally checked out both mechanical and body,

T



nickwarner
Veteran / Moderator
nickwarner profile image

Jun 6, 2012, 4:32 PM

Post #10 of 20 (3936 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Absolutely have it checked. I doubt you'd pay more than $100. Pick a shop you trust and tell them what you are doing. You want an expert third party that has no stake in the vehicle to give you their honest opinion. They will likely find some things, and expect that to happen. Can be a bargaining chip to lower the purchase price for you and you know what you're getting into. They might give you news that this has been really screwed with by people who don't know what they are going and driven hard by an idiot. In that case, consider the fee you pay for the inspection as insurance. Lot of cars look good and drive fine but will be a money pit fast because some shadetree guy rigged it up temporarily. The true pros can find that and be honest about it to you as it doesn't matter one bit to them if you buy the car or not.


Rtodde
Novice

Jun 6, 2012, 7:52 PM

Post #11 of 20 (3934 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Yeah it's a little scary looking into used cars since my current car turned out to be a total lemon! I don't have anyone who really knows about cars and how to spot shady sellers, im going to read up on it as much as possible. My in laws neighbor is has been a Honda mechanic for 20+ years, so I'm planning on picking his brain a little, it's by his suggestion I'm looking at 2000 civics, all he told me us the waterpump+timing belt will always go at 160,000-180,000 km. And that manual could be cheaper in the long run as long as I drive properly. I couldn't imagine driving automatic again, but that's beside the point. I'm finding most civics are selling at 180,000-200,000 km and a surprising amount of 200,000k+ civics with new engines.

Thanks for all the feedback, in regards to my cavalier I drove her about 70km highway + downtown today, and the engine surprisingly did not overheat at all, but since the mechanic gave it back to me I feel a strong smack when I realease my clutch. In first and second gear its impossible to smoothen out, 3rd/4th/5th is much smoother. The power from the engine to the wheels gets more and more sluggish, very rough. As though the engine is ok but not getting to the wheels. If I park a few minutes it goes back to normal. Lots of little things wrong here. I can't imagine her taking me much further.

Any other advice as I venture into the used car market, any other cars I should be considering in the $2500-3000 price range?


(This post was edited by Rtodde on Jun 6, 2012, 8:02 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jun 7, 2012, 3:55 AM

Post #12 of 20 (3923 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

At that price range I find the "old man's" type vehicles the most dependable. Boring but popular cars seem better on the used market. Sports cars frequently have lived a hard life or if excellent would cost more than that price range.

On used market I'd avoid most standard shift cars as you don't know for sure how well the prior owner(s) could drive them and may have stressed out the things. IMO in the used market it will matter more how the car was treated than it's reputation from new,

T



Rtodde
Novice

Jun 18, 2012, 10:56 PM

Post #13 of 20 (3860 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Hey everyone I just figured since I got my laptop back from repairing I would take the time to reply with an update hoping it helps someone in the future.

So as it was I continued to look for a new car and I just couldnt afford it, nothing of decent shape fell into my price range, so I figured I would take some time looking into the problems.

I dont have any intense mechanic experience, Ive changed oil and spark plugs, the coil pack, brake lines, simple stuff with the help of online communities like this one. I always knew my temperature issue could be related to the thermostat being shut but since the car drove poorly even when it was cold I pushed it off for some time not wanting to spend any money on the car. I got fed up yesterday and headed over to my local store and got a new thermostat and gasket, jacked up the car and started to poke around. On the z24 the thermostat is located right under the manifold behind the engine, not the most accessible point, to top it off those bolts were siezed and rusted into place. some elbow grease and a hammer got them loose and out poured green coolant, i was shocked since I had used orange dexcool coolant since Ive owned the car, which tells me this thermostat has been stuck shut for 3+ years!! I took a bath in the stuff to be completely honest....Now ive been driving with the heater or AC to keep the temps down and it looks like the heater core radiator was doing the job of cooling the engine all this time.

Once i replaced the thermostat I took of some pipes to the rad and ensured they were not plugged. and I started the car. to my surprise it ran cool for many many miles but it was a cold night and I wasnt sure that I was out of the woods yet. So today I took a long drive through down town with the heater/ac off and the temps rose and dropped periodically from the combined thermostat and radiator fan doing their job, I'm quite pleased to say the least. Now the gaskets at the top of the engine have been spilling oil on the coil pack/plugs since the engine gets so hot so they will need replacing.

Other than that I do still have some questions since I've just extended the life of the vehicle, when I drive normally the car goes pretty quick, but if I slam my foot to the floor the car looses rpms and power, I'm thinking of changing the air filter and putting some fuel cleaner/additive to a full tank, are there any other suggestions of possible causes for this loss of power besides dirty injectors? I dont think it the plugs since im not puffing smoke out the back or smelling fuel, rather like the engine is not getting enough gas or air. Again Im not to eperienced so any advice is good advice. :) I dont know if I mentioned earlier but the car would make a big smacking sound when I engaged the clutch, my dad looked at it and told me its most likely the universal joint on the drive train since it changes in intensity every time I change gears (even in the same gears), does that sound right? How hard is it to do this repair myself?

Thanks again :)


Sidom
Veteran / Moderator
Sidom profile image

Jun 18, 2012, 11:24 PM

Post #14 of 20 (3856 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Well T stats do stick shut but your time frame is off just a tad......They usually don't quite make the 3 year mark. When they stick you usually have 10 maybe 15 minutes before the temp pegs the gauge and serious damage occurs to the engine....
I really can't give you an opinion on the coolant color other than if you totally empty the system and added dex-cool, at some point....somewhere.....someone switched it back to green.....

As far as the power issue. You could start by having the codes pulled, see if there might be some direction there. I'm not sure how big of a power loss we are talking about but if you have any overdue tune up maintenance to do....Now would be a good time to do it....The air filter would have to be pretty bad to cause that kind of problem but if it looks bad change it out, along with the fuel filter if that hasn't been changed....

On problems like this, it's best to take care of the easy stuff 1st....Sometimes you get lucky & fix the problem in the process....


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jun 19, 2012, 2:38 AM

Post #15 of 20 (3849 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Rtodde - Sidom is right on the mark as usual. No way a thermostat totally stuck shut could make it.

Quick re-read that when you removed the thermostat the coolant was green. Yes the original "Dex-cool" would have been the pinkish/orange and if the thermostat was purposely sealed tight it would still exchange back and forth thru the return hose and in a few cycles would make all coolant the same color. Color is added. The brand "Peak" was once blue - same base of product with a couple exceptions out there that didn't work out so well - yet,

T



Rtodde
Novice

Jun 20, 2012, 6:59 PM

Post #16 of 20 (3826 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

 
hey guys, since ive started driving the car after having it parked for a long while it's been overheating more than usual, recently ive only been able to do 30km's or so before the car became undrivable so if this whole cooling system was plugged I dont know what kind of damage I could have caused. Regarding the two coolant colours I agree it doesnt make much sense that the car could drive at all, but the murky green coolant that came out of the engine was distinctly different from the coolant on the other side of the hose, there must have been some circulation since the green was not as bright as it usually looks on other cars but none the less I am certain there was minimal if any circulation of the coolant. If anything it might have been expanding under heat and back into the reservoir (only one of the two return hoses on top of the rad was ever hot until recently changing the thermostat). Or I was getting circulation through the heater core when I chose to run the heat instead of the ac.

Anyways I`ve been driving all day today and its been great, engine stays under 90`degrees most of the time, in heavy traffic it goes to 95 or so then back to 90 from what I guess is the thermostat+rad fan kicking in. I see there is oil leaking onto my first spark plug and its definately from a broken seal on what I think is the valve cover. I`ll repair that asap when I have the money. No doubt the result of a way overheated engine.

Regarding the loss of power-

I have been driving all day and basically if I push the throttle it`s good until about half way, when I slam it to the floor the engine and rpm bog right down or stay at the same spot. I put good quality fuel system cleaner and then a full tank of gas to see if it made any changes, after a half hour or so I felt some improvements but still nothing to boast about. I changed the fuel filter a few months before parking the car so it should be fine. My next step is to try and clean out the the throttle body (with the spray cleaner) and see if I get any improvements before I move on to sensors or paying for a mechanic to scan for errors.

I`ve been reading all night and people have made 3 common suggestions with other vehicles bogging down at full throttle.
1. Throttle positioning sensor
2. Fuel regulator
3. Catalytic converter creating back pressure.
(this catalytic does look pretty old, it was changed out only 30,000kms or so ago but it's rusted to hell since Ive had the car outside for 2 winters)

Do any of those sound related to the symptoms I am describing?

Thanks everyone!


Sidom
Veteran / Moderator
Sidom profile image

Jun 20, 2012, 8:17 PM

Post #17 of 20 (3817 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

I've only skimmed this thread so I may have missed some details or am repeating some advise. But just going of the last few posts, if you are able to drive around town at low to mid speeds without it overheating and are only having problems at higher speeds you may be looking at a restricted radiator. If you have a temp gun or can feel around, if there are "cold" spots on the rad, this would indicate some passage ways are blocked & coolant isn't flowing thru them. This would reduce the efficieny of the radaitor and it would be noticeable under heavy loads....High speed, going up hill, etc.

The power loss it a little harder without being there. This is where a trained ear or eye is very helpful. Just a quick test drive could reveal if its a fuel or electrical problem. Each has it's own "feel" but is very hard to describe. If you could pull codes or be able to get a datastream to post, one with it running good & 1 with the problem happening would be very helpful. I think I saw where you know a Honda tech? Have him take a quick spin and give you some input.....

Oh...and a Honda is a good choice for a used car but like the others said, get it check out 1st because any car can be abused & then put up for sale to off the problems on someone else


Rtodde
Novice

Jun 21, 2012, 12:00 AM

Post #18 of 20 (3805 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

Thankyou for the quick response, the temperature issues seem to have been sorted out, my temps stay fine at high speeds and under load, if anything there is power loss from heat in extreme traffic + temperatures (30+ celcius/86F). Besides my radiator was replaced with other some other things a year before I parked her. I do still think there is a clog somewhere since like I said in heavy traffic/temps the engine does run a bit hotter and rougher, when I had the cooling pipes opened to change the thermostat I did see a lot of build up inside, so a good flushing out with a pantyhose this weekend might solve the problem.

The power thing like you said is really hard to diagnose, I just got home and was booting around relatively empty streets just opening up the engine, I've been able to squeel my front tires relatively easily and am seeing more improvements in acceleration since i'm up to about 100km with the fuel cleaner in the tank, which to be honest, thought would have little effect on the performance.

I will definately get the Honda tech to take a spin in it, the only thing is the power loss is usually in 4th or 5th gear while at already high speeds, so its going to have to be more than just a go around the block. I'm hoping it's just a sensor but I dont really know where to start, I dont feel like having to buy multiple sensors just to diagnose so my logic says its going to be more cost effective to get the car scanned at a local shop.

I would best describe the feeling as if I had thrown the car into 4th gear at low speed, yes its still driving, but no its not going to move until I putter up to decent rpm's. There is no direct smell of gas or sounds when it boggs down it just feels dead.


Rtodde
Novice

Jun 22, 2012, 6:29 AM

Post #19 of 20 (3789 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

I think I might have an idea as to what it can be after broadening my search into other car models with simillar issues... Vacuum lines. Apparently a leaky vacu line can lead to all kinds of bizarre behavior especially if they are already cracked and heat up... I do hear random hissing after long drives so I'm going to take a good look around for something loose/cracked and let you know if I find anything. Seems like that plus a code read from my local autozone is my cheapest option for persuing these issues... Wish me luck!


Sidom
Veteran / Moderator
Sidom profile image

Jun 22, 2012, 12:19 PM

Post #20 of 20 (3781 views)
Re: Help me diagnose- 1996 Cavalier z24 overheating Sign In

mmmmmmm vacuum leaks normally cause problems at idle not high rpm. At high rpm the volume of air going into the engine is so high that a vacuum leak with have little to no effect on it....
For that problem it almost sounds like a fuel delivery problem but to pinpoint it really takes some specialize equipment since a lot of the times you may get normal fuel pressue reading at idle

One thing you could try would be to get a can of mass air flow sensor cleaner and clean you MAF sensor.....






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