Head gasket or something else?

J

JimPI

New member
Joined
Mar 28, 2011
Messages
2
Reaction score
0
Points
0
2004 Pontiac Montana minivan
6 cyl. 3.4L
70K miles

A week ago, we were driving the van around town for 20 minutes or so and just as we got home, the warning message came on indicating it was overheating. Shut off the ignition and the fan continued to run for a couple minutes. Popped the hood a few minutes later. No steam, no hot "smell" at all. Coolant level in overflow tank is fine, about 1/3 full. Next day, started the van up and the warning message came on saying the van was due for an oil change. Just had it changed a month ago and have only driven a few hundred miles since then. Drove it around for about 20 minutes and the temp gauge never got above halfway.

Took it to a local dealership and they said it had a blown head gasket, repair estimate $1500. The son of a buddy of my Dad is a mechanic so I had him come to my place and look at it. No signs of coolant leakage anywhere externally. Coolant level in radiator fine. Checked the oil via the dipstick and it looks normal, not cloudy or "creamed coffee" colored at all. He had a portable code scanner with him and that didn't show any errors at all.

Dealership shop says the oil via the dipstick would look fine as oil floats on top of water and the stick only reaches the top quart or so of oil. Others have told me if the head gasket is leaking internally, the oil will not look right via the dipstick.

Keeping in mind I know little to nothing about engines, is there any definitive way I can determine if the head gasket is indeed faulty or if instead it was just some sort of glitch with the sensors and the dealership is just looking to screw me? In doing some research online, the Montanas have a reputation for blowing head gaskets at 70K miles so it wouldn't surprise me if it was indeed bad. But, all indications I'm seeing tell me the head gasket is fine?

Any input would be greatly appreciated.
 
Did it over heat (looking at the needle)? The only way it would show on the dip stick is if the coolant was leaking into the oil (I know it does this on intake gaskets sometimes) and I would go to another dealership if they say it won't show on dipstick if it is leaking internally into oil. They are lying. My Malibu (3.1) went bad three times by the time I sold it and every time it leaked inside and the oil and coolant does mix.

If your coolant level is fine and you are not having to add any, I don't know really.
 
Y'know, when I saw that warning message about it overheating, I had just pulled into my driveway and immediately shut it off without looking at the needle on the temp gauge. I've been kicking myself for that ever since.

It shows no signs of leaking externally--no puddles under the van, no signs of wetness anywhere under the hood. I was told by the dealership that it was leaking internally. But, I'm of the understanding that IF it is leaking internally, it would be in the oil and thus show on the dipstick?

Is it possible for it to be leaking internally and not show up on the dipstick at all?
 
Overheating without major coolant loss typical of a headgasket failure. I've probably done 30 or more montana's with that problem. They make a combustion gas test kit to check for headgasket leaks.
http://ezblocktest.com/
______________________________
 
planenut good call had a suburban once with a bad intake gasket and it had a sweet smell in the exhaust ,I didn't notice it till the mechanic alerted me to it then I could smell it but there was no signs of it . I guess it was such a small leak that it didn't show up anywhere else yet . That may be whats happening to you.
 
JimPI said:
2004 Pontiac Montana minivan
6 cyl. 3.4L
70K miles

A week ago, we were driving the van around town for 20 minutes or so and just as we got home, the warning message came on indicating it was overheating. Shut off the ignition and the fan continued to run for a couple minutes. Popped the hood a few minutes later. No steam, no hot "smell" at all. Coolant level in overflow tank is fine, about 1/3 full. Next day, started the van up and the warning message came on saying the van was due for an oil change. Just had it changed a month ago and have only driven a few hundred miles since then. Drove it around for about 20 minutes and the temp gauge never got above halfway.

Took it to a local dealership and they said it had a blown head gasket, repair estimate $1500. The son of a buddy of my Dad is a mechanic so I had him come to my place and look at it. No signs of coolant leakage anywhere externally. Coolant level in radiator fine. Checked the oil via the dipstick and it looks normal, not cloudy or "creamed coffee" colored at all. He had a portable code scanner with him and that didn't show any errors at all.

Dealership shop says the oil via the dipstick would look fine as oil floats on top of water and the stick only reaches the top quart or so of oil. Others have told me if the head gasket is leaking internally, the oil will not look right via the dipstick.

Keeping in mind I know little to nothing about engines, is there any definitive way I can determine if the head gasket is indeed faulty or if instead it was just some sort of glitch with the sensors and the dealership is just looking to screw me? In doing some research online, the Montanas have a reputation for blowing head gaskets at 70K miles so it wouldn't surprise me if it was indeed bad. But, all indications I'm seeing tell me the head gasket is fine?

Any input would be greatly appreciated.
Click to expand...
hey how convienent i just did a head gasket on mine i actually ended up buying twoo kits for it and the total for the parts oil filter and oil was around 500 bucks i did it my self cause me and my buddy are goin to be mechanics so it was just good practice id talk to ur buddy and see if he wants to do it as a side project it took me and my buddy about three weeks but we both work 2 jobs and go to school
 
Have the radiator checked for hydrocarbons. There is a sniffer that will detect this. If they are present in the radiator, the head gasket is leaking.
 
I re-read your initial post. If you are NOT losing coolant, it`s either a stuck thermostat or a faulty temp sensor. If your rad and resevoir levels are fine, then its NOT a gasket problem. The only other thing it could be is that the cooling fans are not comming on.

I guess you could have a wire to the temp sensor thats grounding somehow giving a faulty reading....

And yes...the intake gaskets can leak into the air intake only and so you would NOT see any signs of coolant in the oil. But as previously stated, you would probably smell it in the exhaust if it was a bad enough leak.

This is just my opinion, but your motor is still a little young to experience gasket problems but NOT unheard of. BUT, with your mileage I would assume it would be just the lower intake gaskets...not the head gaskets too unless you have truly overheated the motor and you`ve warped a head.

Ian
______________________________
 
corrections

ianmcdca , I just wanted to make a cpl corrections ,,,,,,first it could also have been a water pump issue although not real common it does happen ,,,,,and second the intake gaskets both at the front and rear seal the coolant passages through the lower intake into the heads and further into the block so lower intake gasket leaks can and often do leak coolant into the engine oil and sometimes also oil into the coolant which is kind of strange but I've repaired 4 or 5 chevy 3.4L engines (Venture, Montana,,,,,,,etc) where the intake gasket leaks went into the oil and oil into coolant .
 
You must log in or register to reply here.

Share this page

Back
Top