Main IndexAuto Repair Home Search Posts SEARCH
POSTS
Who's Online WHO'S
ONLINE
Log in LOG
IN









Search Auto Parts

Tiny bubbles in overflow tank but passes Block Tester?


  Email This Post



Fur Trader
Novice

Jul 29, 2015, 11:41 AM

Post #1 of 17 (5700 views)
Tiny bubbles in overflow tank but passes Block Tester? Sign In

2000 Nissan Maxima VQ30DEK (3 liter V6), just hit 170k miles.

Relevant history: new radiator back in October - car is a rebuilt front-end wreck, dirt-lot rebuilder installed AC hard line rubbing on radiator, lasted 3.5 years until it rubbed through and began to drip. Driveway stains alerted me before any overheating.

Current status: So it got hot after a long freeway run, coasted home with gauge high but not at limit. Let it cool and dude where's my coolant.

Refill rad, burp, repeat.
Check for fans, they run and are loud on these cars.
Mark level on overflow tank, see it's higher after driving - so coolant is getting pushed into overflow tank until it overflows. No coolant left to cool, doh!

Observe tiny bubbles in overflow tank. Excess in tank does not suck back in during cool down.

New thermostat, new rad cap, more filling and burping (am now pro-level Maxima cooling system burper) - but it still does bubbles and pushes out.

Rent block tester and buy fluid, run test on overflow tank - negative. Run test on radiator BUT when cold, not warm, negative but doubt validity of test. I don't dare let this thing get warm with the cap off.

Drive for an hour at less than 70, few bubbles but no pushing into overflow tank. Take it up to 80mph for a few miles and get some push out. Also ambient temps 101 F, is Texas.

Don't really want to do the head gaskets. I hate working on FWD V6s and feel dumb for buying one even if it does haul butt (especially when cold and on 93 octane!). Also, current financial state is one of low liquidity. Thankfully we didn't sell wife's old car so I have backup transportation, rusty Mazda Protege5 with half the power and twice the handling of the Maxima.

Might try the fancy $40 nano-fiber-magic head gasket sealer bottle, but have read horror stories of dead motors with clogged coolant passages from them.

Thoughts?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jul 29, 2015, 12:12 PM

Post #2 of 17 (5688 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In


Quote
Might try the fancy $40 nano-fiber-magic head gasket sealer bottle, but have read horror stories of dead motors with clogged coolant passages from them.


Bad idea.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Fur Trader
Novice

Jul 29, 2015, 12:51 PM

Post #3 of 17 (5684 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

What's driving me mad is really the negative block test, no hydrocarbons detected. What the heck else causes tiny bubbles and overpressure? No leaks or noise from waterpump, which is hard to reach being behind the timing chain under some access plates.

In Reply To


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 30, 2015, 4:03 AM

Post #4 of 17 (5669 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Quote from top post">>Excess in tank does not suck back in during cool down.<<"


Just that suggests either hose from radiator to tank isn't tight and sucks back air not coolant or cap isn't holding pressure for some reason even though a new one.


With zero pressure you'll boil over beating on this thing especially at high ambient temps it's not going to take that. That would blow out bubbles alone and is overheating but if system isn't tight is not going to draw back coolant or cap maybe never held pressure. Pressure test anyway system and cap.


Block test failure doesn't rule out head gasket IMO. It was quite low on coolant and running hot by gauge you said so in the territory for trouble.


Air left in systems when drained doesn't all come out usually for several drive cycles of cold to fully warm but if it can't draw back coolant it drawing back air so even if you had it full is isn't after first drive.


Head gasket(s) not ruled out yet. Things to check and do:
*Antifreeze not too strong - check it. More than 50/50 will not transfer heat well and be the cause of overheat if way too strong.
*If not holding pressure boiling point is still too close to plain water. Read antifreeze container it says raises boiling point but also says with a working 15lb pressure cap(system) also which is most of it.
* If blowing gasses into cooling system most would pressure up and you'd feel upper hose fill with pressure fast from cold start up before it had time to warm up - damning clue of head gasket.


DON'T USE A SEALER OF ANY KIND unless you are buying time to get it to a salvage yard again. It won't fix a head gasket and will clog things up,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jul 30, 2015, 4:54 AM

Post #5 of 17 (5662 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In


Quote
What's driving me mad is really the negative block test, no hydrocarbons detected. What the heck else causes tiny bubbles and overpressure? No leaks or noise from waterpump, which is hard to reach being behind the timing chain under some access plates.



Those fluid detectors are total inclusive and only show positive when it's so bad it's completely obvious. The only real accurate way to test is to use an exhaust analyzer to sniff for hydrocarbons at the radiator cap.

Another DIY trick is to put a latex glove around the filler cap tightly and run the engine. If the glove inflates, that's a pretty good indication of gases getting in.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Fur Trader
Novice

Jul 30, 2015, 6:54 AM

Post #6 of 17 (5655 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Holy crap you guys.
After reading your replies this morning two things pinged together in my brain:
A) Tom's pointing out that the lack of coolant being sucked back in from overflow tank during cool-down is a clue, and
B) Hammer's trick of putting latex glove over filler cap to see if it inflates.

The ping result was: what if the coolant overflow tank is not airtight? I know it looks old and faded.

So, while leaving for work I popped the hood of the Maxima and examined the reservoir. On top, there's several patches that are bleached white and have spidercracks in them. Aha! Then I pushed on one with my finger to see if the cracks would open. See photo for result of that test.
Calling around to junkyards now for a replacement.
Kinda kicking myself, I have been messing with this tank for days and ignoring it's poor condition.

[URL=https://imageshack.com/i/p96s7Ov4j]Pirate


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Jul 30, 2015, 7:34 AM

Post #7 of 17 (5651 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Don't think that is your problem. The reservoir is not designed to be air tight. It is actually vented. You should use a coolant pressure tester to make sure you don't have any leaks and you should follow HT's advice on finding out if there is combustion gasses in the coolant system.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Jul 30, 2015, 7:35 AM)


Fur Trader
Novice

Jul 30, 2015, 7:46 AM

Post #8 of 17 (5646 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Will do. I have a local shop near my work with top-notch customer service, I'll have them run pro-level sniffer test.
But first I have to replace the broken tank, there's chunks of disintegrating plastic floating in it now. It crumbled like a pastry!


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 30, 2015, 8:39 AM

Post #9 of 17 (5643 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

That tank isn't pressurized sport some have the pressure cap on that - this doesn't. Fine, it's bad but you said it was holding a level and wouldn't drop or draw that back in which is probably the second part of the real problem. Junk all floating around now or all of a sudden is probably debris from a very harmed engine - guess.


If gas test was done at that broken tank which is an iffy test to begin with it's the wrong place with a bad tank so no surprise that didn't help,


T



Fur Trader
Novice

Jul 30, 2015, 9:07 AM

Post #10 of 17 (5638 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Pretty sure the junk is from me poking my finger through the crumbly tank, I haven't got any oil sheen or debris from the engine in there. I actually siphoned out that tank into a clean bucket when I was doing the block tester test Sunday, because it was almost filled to the top, and reused the clean-looking coolant when I was done. Never noticed the cracks during.

Also wondering about too thick of a mix. Have so many random half-empty jugs of coolant laying around (replaced this Maxima's and the Mazda's radiators like a month apart last year!).


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jul 30, 2015, 9:30 AM

Post #11 of 17 (5635 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Your block tester is not going to work on a non-pressurized tank. It has to be done at the radiator.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Fur Trader
Novice

Aug 12, 2015, 7:56 AM

Post #12 of 17 (5588 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Well it's official. Took it to my trusted shop and they did the Block Tester correctly - confirmed BHG.
Frown
It's also nearly a grand cheaper to have them swap in a used motor than it would be to have them do the head gaskets.
The local yards are advertising these motors at around $450ish. I may swap it myself, though making room in my garage may be more work than the actual swap.
Also tempted to upgrade to a later VQ35 mill for more horsies & torques, though that means tranny and ECU also.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 12, 2015, 8:36 AM

Post #13 of 17 (5587 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

From just your subject line this SCREAMED of a blown head gasket! You decide on another engine or fix what's there. I wouldn't ever get a whole used engine that wasn't an exact match - enough troubles already with this.
That recovery tank needs replacing if that brittle but think it was working as a tank if not leaking at the bottom parts.


IMO - somehow the plastic got way too hot to be brittle like that. Most never do that without trauma.


You now know the problem or are convinced so choose your plan of fix carefully,


T



Fur Trader
Novice

Aug 12, 2015, 9:05 AM

Post #14 of 17 (5583 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

I'm also toying with selling the car for a few hundred bucks as-is. I do need a truck.
~
I had figured the plastic of my overflow bottle had been heat-damaged in the past, until I poked my finger through the three more in one junkyard (a Maxima, an Altima, and an I35). Oddly, the same weak point on mine and the others is right under the hood gap. Granted, those cars may have also landed in the yard due to BHG! The yard had spraypainted a red X on the Max motor but the other two are available.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 12, 2015, 10:15 AM

Post #15 of 17 (5577 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

OK - You seem to have answered this on your own now knowing ONE lousy issue to get thru.


Your call, My thoughts: It was a salvaged cobbled car from the get go and you really would rather have a truck. Well, now is the perfect time to get what you can and do search out what it's worth just as it is and don't waste more money on it if not ever wanted so you just said.


You may be surprised as what parts that are still good can be worth to a salvage yard - interior stuff if any good hard to come by if still good. Glass, doors, body metal and so on. Then when plucked of anything useful just it's metal squished is worth some bucks!


Whole cars can fetch assorted scrap values - check around. If one nearby and it still will run they will (do where I am) make an offer on the spot - here need proof it belongs to you of course.


The choice is that and possibly a very costly fix of this one or cut losses now and move on to a vehicle you do want more. What would it be worth without the problem now vs having it? Just do the math.


You even thought of changing this to another engine I think you meant. NO! This is still and OBDII vehicle. The hassles of alterations on this salvaged already car would be an endless nightmare.


Whole engines at junk yards: Did that for many. Wanted to see why the vehicle was available and hopefully just a wreck and still could run it. My own local yard would then test all they could and provide a compression test, known miles and a list of checks and save them or like you said the Red X - just forget that one. Let those be "core" parts if they are in demand for the exact motor.


Hey - cutting losses IS SAVING $$ so do the math.


With all that I'd move on and spend time and effort on the next thing that you want, not this one,


T



Fur Trader
Novice

Aug 12, 2015, 10:28 AM

Post #16 of 17 (5573 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Good points, thank you Tom.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 12, 2015, 11:05 AM

Post #17 of 17 (5571 views)
Re: Tiny bubbles in overflow tank but passes Block Tester? Sign In

Yea - Really think NOT wasting good money on this one is the choice.
Vehicles are a hole you always just pour $$ into no matter how you cut it.
Best bets for next: Really take your time and check out the next, even pay for it to have a pro go thru it to find any possible hidden problems BEFORE putting dime down on it. If a seller doesn't allow screams move on to another.


Start off with the best possible thing including that you plain like it and serves the purposes you want or need it for. This one fails on all fronts if it was new doesn't seem like you'd keep it long.


Good luck with what you do or get. If not totally a new vehicle with long total warranty there will probably be something to do soon enough.


No joke. The effort and even paying more for exactly what you will know you'll like and isn't a know POS by design is the best way to not lose as much. They all are money pigs,


T







  Email This Post
 
 


Feed Button




Search for (options) Privacy Sitemap