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the 3400 Motor


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Zeal
New User

Jan 20, 2013, 10:21 AM

Post #1 of 7 (1532 views)
post icon the 3400 Motor Sign In

So my buddy did a Head Gasket for a 3400 Motor, and it was still over heating in the end, he ended up passing on fixing the job. He did torque it down with a torque wrench but it was his first Head Gasket. He's the type of guy that always has to do it right, so I have confidence in his work. Some other mechanic came around, and said he had to replace the head on it, now it runs.
It was a 99 Buick Century, 3400 Motor.

I am currently looking to buy a Chevy Venture, with the same 3400 Motor, the girl says her buddy put a Head Gasket in it, but it was still overheating. The guy did not use a torque wrench, so its not torqued down.. Shes looking to sell.

So what im wondering is, if anyone with experience with these motors, know if when the head gaskets go, the heads go on them too. What are some of the common problems with these motors? I went and checked all the Junk Yards in the area, and found the motor everywhere, atleast like 20.

Since I am looking to buy and fix that minivan, I really don;t want to pull the whole motor if I dont have too, since its such a tight fit, there is no room. If I could get away with just torquing it down, or putting a new head on it, I'd love to do that.

Any Advice on this 3400 Motor would be greatly appreciated Thanks.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jan 20, 2013, 10:57 AM

Post #2 of 7 (1506 views)
Re: the 3400 Motor Sign In

Are you kidding? Install a head without torquing the bolts?

Not only are there specific tightening sequences but the head bolts cannot be reused.

These are torque to yield bolts, also known as stretch bolts. They are one time use only.



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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.



MarineGrunt
Enthusiast
MarineGrunt profile image

Jan 20, 2013, 1:52 PM

Post #3 of 7 (1490 views)
Re: the 3400 Motor Sign In

We have a 2002 Chevy Venture and I have done a lot of work on it recently. In the last few months I rebuilt the tranny and also replaced the head gaskets. When I removed the heads I took them to a machine shop to have the planed and pressure tested for cracks. Both of my heads were fine to reuse. So no, just because the head gasket goes doesn't mean the heads are toast.

It's no wonder the van you're looking at is still overheating. Like HT said, you have to use new head bolts and HAVE to torque and follow the tightening sequence. If the guy didn't have enough common sense to use a torque wrench it's hard to say what else he screwed up on it. I'd look it over real good. Better yet, take it to a pro and have him look it over. Maybe it's overheating because the guy filled the radiator with brake fluid instead of coolant. Cool

If you do decide to get it make sure you take the heads to a machine shop. I think I paid around $150 total for both heads to be pressure tested and planed. As long as the van wasn't driven for a long period of time while it was overheating there's a good chance they'll be good to go. You never know though. The pressure testing was $30 a head so worse case you'll be out $60 only to find out you need new heads.

As long as you take off the motor struts and use a ratchet strap to rotate the engine forward it's not bad working on it. Like you said, it is a bit tight though. It took some time for me to get use to it.

One of the most common problems with the 3.4 is the intake. We bought our van with I think 30k on it. We drove it until 140k and the only thing I had to replace was the ac condenser. Other than that it was a great running van. Once it hit 140k is when I had to do the intake, then tranny, and then head gasket. I think overall it has been a great running vehicle. I think the reason there are so many at the salvage yard is because it's a popular motor. My thoughts are is if they have 20 of them that means the engine outlasted the car. That's a good thing if you ask me.


(This post was edited by MarineGrunt on Jan 21, 2013, 10:36 AM)


nickwarner
Veteran / Moderator
nickwarner profile image

Jan 20, 2013, 9:12 PM

Post #4 of 7 (1475 views)
Re: the 3400 Motor Sign In

If this person lets just any Cletus work on this, walk away. There's no telling how many issues have been neglected or sent to the lowest bidder that will come back to haunt you badly. If someone doesn't even know how to torque heads properly, they have not one bit of business touching that job and I guarantee there is a lot more cobbled up crap on that then you realize. Don't just walk away from it, run.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jan 21, 2013, 4:08 AM

Post #5 of 7 (1465 views)
Re: the 3400 Motor Sign In

I'm still trying to figure out what MG's picture is.




Whooo, it disappeared after i posted.



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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.



(This post was edited by Hammer Time on Jan 21, 2013, 4:10 AM)


MarineGrunt
Enthusiast
MarineGrunt profile image

Jan 21, 2013, 10:39 AM

Post #6 of 7 (1451 views)
Re: the 3400 Motor Sign In

I don't what the heck that was HT. When I first posted the pic it was the tightening sequence. Today, once I hit edit, I could see it and I have no idea what it was. Looked like something on the side of the oil pan maybe. I guess I first should've started with a picture of a torque wrench.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jan 21, 2013, 4:04 PM

Post #7 of 7 (1442 views)
Re: the 3400 Motor Sign In

Like I warned you, you can't copy and paste most things from Alldata



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

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.







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