Failed block test

[Chevy3500]

Ok i currently am a mechanic at a shop here in town working full time. I have a great deal of knowledge but am still learning and ask for help when i need it. I am working on a chevy corsica i think thats what it is. Well the guy brought the car back twice saying it would over heat and me and the other mechanics noticed their is blueish vapor coming from the tail pipe . Well i couldnt get it to over heat so i figured it was get excess pressure in the cooling system from a blown head gasket. Well i let the car get it op temp and did the block test and sure enough their was combustion gases presence in the cooling system. I am trying to narrow down which cylinder is leaking into the combustion chamber. I tryed to fill the combustion chamber with 80 psi and put a gauge on the cooling system and the gauge didnt rise, is their anyother easy way to narrow down where its leaking. and help would be great thanks

 

[ak diesel driver]

thinks it's enough that an infared heat gun would be able to measure a cooler exh manifold?

 

[Chevy3500]

I dont think so because you can fill the cooling system with 15 psi and it holds pressure, it seems to only leak when its warm

 

[WarWagon]

V6? 4 cylinder simply doesn't matter. Leaking hot has head crack written all over it. If it is a 6 cyl you can pull the coolant crossover off with the engine still full of coolant and water pump belt off. Start the engine and see what side is bubbling. May have to warm it up a little - but not too long with no coolant flow.

 

[Chevy3500]

Its a v6 but the coolent crossover is a pain to get to its right up against the exhaust manifold the motor is 3100 v6

 

[tanman_2006]

My sisters car with that motor blew 2 intake manifold gaskets. I didn't change them out but that's my experience with that motor.

 

[Chevy3500]

I guess the customer picked the car up over the weekend

 

[WarWagon]

My sisters car with that motor blew 2 intake manifold gaskets. I didn't change them out but that's my experience with that motor.

X2 on the 3.1's. The intake manifold gasket leaks coolant into the oil. Usually wipes the cam bearings if let go too long. IE engine simply locks up... Could leak coolant into the intake as well. Did any of the intake bolts you could see have coolant puddle or traces of evaporated coolant on it? Not a bad job to do. You will need the special torx bolt socket and fuel line clip tools over the normal tool collection. Inch pound TQ wrench may also be needed but my memory is rusty.

Have the service writer call the customer back. Quote em an intake manifold job with a backup quote for heads. I had head work done on a friend's 3.1 for $1200 including a valve job as the water pump failed and took the gaskets out. Not sure how you get paid and what kind of deals you can cut the customer, but, this would be a good experience job for you if you are not too busy. These jobs will bite you in the butt, but, a good way to learn the engine. Lot of 3.1's out there with intake manifold gasket leaks.

The intake manifold gaskets may not be the only parts you need as the sealing surfaces pit badly with the Dexcool. I slapped new gaskets on my sister's car that had bad pitting at the coolant sealing areas with 50K on it and they were holding at 170K several years later.

 

[Chevy3500]

I guess this customer trys to do the work himself,he has us figure the problem out and then trys to do the repair. I have done intake gaskets on a 3.8 but not on the 3.1. Im pretty sure you have to also remove all the push rods in order to remove the intake gasket and the trick is each push rod is a different length, so put the push rod in the worng spot and they goes a valve and push rod. Their isnt much i havent done even though ive only been in this shop for about a year, I can do ever thing the other guys do and some i can do better than them. Like me and my boss are the only ones who can weld ( I weld better than my boss), and i know more about the diesel that come into the shop. But i love learning new things and i like to get faster and faster at it. Everyone has room for inprovement, Sorry for the blaha blah blah

 

[6.2 turbo]

They only have two sizes of pushrods.

 

[countryboy69]

yes 3.1 and 3.4s both have the intake gasket issue. Yes only 2 sizes on the push rods. tighten the rockers slowly tho. They have auto lash setting lifters. Sometimes they are a pain. But anytime you have a 3.1 or 3400 check those intake gaskets. Look for moisture in the oil. Check both the dipstick and the 710 cap(OIL upside down!).

 

[WarWagon]

Pushrods do not have to come out on the 3.1's for intake gaskets. You should call the customer and let them know the intake manifold could be their only problem. They will remember it. Slow days things like this keep the lights on.

I take things I don't want to do to a local shop. I take them my own parts as well. Sometimes a 2nd opinion is worth the diagnostic fee like when bad plugs and wires are tripping a cam sensor code on a Saturn.