Intake manifold leak?

[SierraK1500]

I have a 2005 3.4L engine in my Impala. I took the car to a a national dealer to have my tire repaired and to have the oil changed. During the whole time I have had this car I have never seen any grayness or antifreeze in my oil.

I received an estimate of $732.08. To replace the intake manifold gasket.

Who's trying to rip off who?

The car has 115,000 miles on it. Runs a good as the day I brought it home from the dealer. Gets great gas mileage and is a good vehicle. To prevent a lawsuit I will not mention the name of the Tire Company. They have found a problem with this car since day one. Rear out of alignment, a bad left front wheel hub, valve cover gaskets and now this. There is nothing wrong with the car.

I will continue to monitor the color and smell of the oil for the next 30 days. They told me to check the oil in 2 weeks. ALARM! If the head gasket was bad would it not contaminate the oil soon as I drove the car home from them? I drove it 15 miles.. checked the oil and looks and smells brand new.

I cannot wonder for the life of me that now why someone else who is just as money hungry tell me this before. These ppl trying to rip me off?


Ok forum tell me what you think.

Thanks!

[SierraK1500]

I have been checking the oil every time I have driven the car and it looks and smells good. What are your thoughts? I need some input before I go screaming ripoff......

[Iflylow]

If you are not losing coolant, and do not see oil in your coolant, you do not have a leak.
What evidence did the shop present to say you had a leak?

The 3.4 is known for upper and lower intake mainfold gasket leaks, but the gasket design was changed in 03 (I think) and the problem was not nearly so common with the newer gasket.

[91 bird]

i just changed a head gasket on one of those motors. you can pull the oil cap and look at the bottom of it. if it looks like a melted vanilla shake, then there is antifreeze in the oil. if not then no leak.

[SierraK1500]

Thank you all for your input. I did just what y'all suggested and checked the oil and the oil cap for the vanilla milkshake effect. Its is all clean. I feel the company tried their best to rip me off. They didn't succeed this time.

[Ruley73]

Originally Posted by 91 bird

i just changed a head gasket on one of those motors. you can pull the oil cap and look at the bottom of it. if it looks like a melted vanilla shake, then there is antifreeze in the oil. if not then no leak.

This is not an accurate way to determine whether or not there is a coolant leak.

Condensation often accumulates in the valve/cam covers near the oil cap if the engine doesn't get warmed up enough to boil out the moisture. It looks like a frothy milky substance. This is completely normal for any car, and usually happens when the car is driven short distances in cooler weather.

AFAIK GM has still not completely fixed the upper/lower intake gasket leaks on the Chevy 60-degree-V V6 engines (this includes the later 3100 & 3400 engines); despite some gasket revisions through the years.

The OP may very well have an intake manifold gasket failure (different from head gasket failure). They just need to keep an eye on the coolant level. The coolant doesn't always mix with the oil when the IM gaskets fail. The stuff the OP says the repair place has found wrong with it seems legitimate given the cars age/mileage.

[maxwedge]

Originally Posted by Ruley73

This is not an accurate way to determine whether or not there is a coolant leak.

Condensation often accumulates in the valve/cam covers near the oil cap if the engine doesn't get warmed up enough to boil out the moisture. It looks like a frothy milky substance. This is completely normal for any car, and usually happens when the car is driven short distances in cooler weather.

AFAIK GM has still not completely fixed the upper/lower intake gasket leaks on the Chevy 60-degree-V V6 engines (this includes the later 3100 & 3400 engines); despite a some gasket revisions through the years.

The OP may very well have an intake manifold gasket failure (different from head gasket failure). They just need to keep an eye on the coolant level. The coolant doesn't always mix with the oil when the IM gaskets fail. The stuff the OP says the repair place has found wrong with it seems legitimate given the cars age/mileage.

Spot on onfo!

[wafrederick]

The after market did fix the intake gasket problems on these engines.Dorman has a kit with the gaskets made out of metal instead of plastic also coming with new intake bolts.Fel Pro does too,made out of metal with out the new intake bolts.The Dorman kits is cheaper than the upgraded Fel Pro gaskets

[Ruley73]

Originally Posted by wafrederick

The after market did fix the intake gasket problems on these engines.Dorman has a kit with the gaskets made out of metal instead of plastic also coming with new intake bolts.Fel Pro does too,made out of metal with out the new intake bolts.The Dorman kits is cheaper than the upgraded Fel Pro gaskets

Yes, I believe the Dorman kit (p/n 615-205) has the most reliable gaskets for this application. They have revised their kit once within the last 5 years as well (old p/n was 615-200). I don't have any first hand experience with them, but I believe the Dorman products are generally of very good quality. I've heard some bad things about their chassis parts though (i.e. the ball joints in their control arms wear out prematurely).

[Colt Hero]

I've got a 2002 with the 3.4L engine. My experience was a visible leak on the side of the block along the thin black diagonal "V" seal behind/beside the power steering pump (the side with the Serpentine belt). There's a natural (casted) trough below this seal where sand collects. The cooland drips down the side of the block into this sand-filled trough creating a muddy mix. No coolant reaches the ground.

Also, the plastic coolant tank gets kind of oily-looking inside. The drop in fluid level may not be easily detectable - even over several weeks or months.

Pull off the radiator cap and look on its backside. Mine had a fudgicle-sludge mix smeared all over it.

Lastly, the "LOW COOLENT LEVEL" alarm/message may appear on your dash. This is due to the sensor on the radiator (plugged in just below the filler neck opening) getting sludged up. You can remove it and clean it, but if you have a leak, the message will return.

I figure my engine starting leaking at around 65k. I lived with the leak, monitoring fluid levels and checking for more concrete evidence until around 104k when the engine started getting noisier (lifter damage due to contaminated oil). Finally, I replaced the gaskets myself for around $400 (including plugs, wires, lifters, hoses, and every gasket I touched).

I'd also add that we had a company car Impala which was a 2005 and it had the same damp spot/leak on the side of the block near the PS pump, so it was most likely headed for the same result...

[SierraK1500]

I appreciate everyone's input. I just finished driving the car to Corpus Cristi, Texas twice from Dallas, and beat the tar out of the engine to look for a leak. Nothing had entered the oil and the motor dosen't smell like antifreeze. I really do believe that the tire dealer was trying to rip me off. Car ran extremely well, and never missed a beat. I even had her up to 95 on US Interstate 35 (had radar detector). No problems!

John

[Colt Hero]

Please keep an eye on your engine. This leak is a very insidious one. As I said, it took me some 40k miles to believe that I had a leak. It was a VERY slow leak up until the very end when it started to leak a LOT MORE visibly. I finally ended up putting a tiny bottle of green dye into my radiator, checking the block week after week. Don't remember how long it took but eventually I saw green bubbles coming out the "V" seal and dripping down into the trough below.

You can also have a leak-down test performed to determine if there's a leak. I didn't do this because I was afraid that I would just be giving some mechanic an excuse to charge me for an intake gasket job (that's why I used the dye myself).

Personally I think this problem is a chronic, long-term one that you can live with for a while (as long as you keep an eye on it). With my car, coolant was mixing with my oil, so I was slowly damaging my engine. But I was also monitoring the coolant loss on a regular basis and changing my oil every 3000 miles, so how much damage did I do (and how long could I have gone on like that before the engine quit on me)? Who knows?

I also think ALL of these 3.4L engines leak. As I said, I saw a 2005 company car Impala with the same leak, so I don't think GM ever fixed it (properly). GM ran the Venture van for close to 10 years with the same crash cage that folded like a house of cards (crushing the dummy's legs) in the IIHS test. They never redesigned it to make it safer. So if they're going to ignore serious safety issues (GM told me they only paid attention to ACTUAL crash data, NOT what the IIHS findings were), why would they fix a leaky gasket?

[SpinnerCee]

It's basically a materials/design issue -- plastic (upper intake) and aluminum (lower intake/cylinder head/engine block) expand/contract differently in response to temperature, so this constant "movement" inevitably will cause seal wear and thus leaks. The design problem comes from allowing/requiring coolant to flow around or through the junction of parts with such different characteristics.

The "better" gaskets incorporate metal which is more resistant to fatigue from the heat/cool cycles.