I flushed out my cooling system to day and I went to refill it and I had the front end jacked up and the engine warmed up using one of the 'no spill' radiator filler funnels. Then I thought I had all the air bubbles out after about 15 minutes. Then more bubbles came and more and more. Just little bubbles one after another. In my experience with other cars this means that the head gasket is blown somewhere on the compression side of the cylinder. What are your thoughts? I have not done a leak down test yet.

Bruce

 

Head gasket or water pump. Go to a shop to see if there are any hydrocarbons in your radiator to rule out the water pump.

 

head gasket blown,,is there any white smoke coming out the tail pipe,,

 

Absoulutely no white smoke whatsoever.

 

why did you flush your cooling system?

maintenance? was it running hot? does it overheat now?


if you just drain and fill it, there shouldn't be bubbles in your coolant, unless there is air

 

I had been over heating so I changed it. By bubbles I mean about the size of peas not just little foam bubbles. Update: the car is in the shop now, water pump or maybe a head gasket.

 

well, since the VQ isn't known to have water pump problems, it sounds like a blown head gasket even though you have no white smoke from the tail pipe...could be a hole in the gasket on the combustion side ..

keep us updated

 

yea right. VQs have water pump problems and i bet thats what it is.

 

i read someone post saying that they're Nissan dealer had never sold a water pump ( yeah i know ) because they never go bad ( according to the post )

if it locked up ( timing chain driven ) then the chain would have gotten locked...i could see if the water pump was belt driven on the outside it could overheat...unles the water pump blades were somehow stripped or came apart and the pump is just spinning w.o blades thus causing it to overheat ...


i'm curious to know what they found ?

if he had done a combustion chamber leak test it would have confirmed or denied the water pump

 

Overheating + Bubbles/Air in the cooling system = blow head gasket.

 

Ok here is the latest. Mechanic said that the hydrocarbon test was negative so at this time he cannot confirm a blown head gasket. He took it driving to try and replicate the overheating and he cannot make it overheat. So his thought is to drive it some more and see if it will over heat for him. He seems to think that I just didn't get all the air bubbles out of it when I changed the coolant.

 

That was me. Local dealer doesn't stock the water pump (that I thought I needed), but DID have the oil cooler water pipe in stock (that I DID need!).

 

why did you need a oil cooler water pipe?

 

Leaking from rust.

 

phew! looks like you dodged a bullet....

 

Well here is some more information about the hydrocarbon test... He said that if it is positive, than it is 100% that the head gasket it blown. If it comes back negative, which it did, that it is NOT 100% accurate that the head gasket is blown. So right now I am at the point where he has had it for three days and knows as much as I did when I gave it to him.

Not that I don't trust him but I want to get the maxima out of the shop and give it back to my wife so I can have my Tahoe back...woman is killing my gas mileage.

 

hhhhmmmm i've always known the combustion leak test to be 100% accurate, the liquid turns yellow when it detects combustion chamber gasses....


unless he's not doing it correctly

 

Yeah I've got nothing...I am at a loss.

 

So I just got the car back tonight and everything is fine and all he did was fill and burp the coolant system and do the dye test. I am thinking that maybe it is a warped head or a hairline crack of some sort that needs the head to have a good bit of heat in it before the metal will expand enough to manifest the symptoms i.e. bubbles in the coolant.

 

Well I finally fixed it....I sold it.

 

what did you do to fix it?

 

 

ah ok now i understand ..he just got rid of it

 

I could literally see the "WTF" look on your face as your wrote this.

 

That seems to be the way ppl cure their problems these days....But that's what happens when you ignore dealing with an overheating car with an all aluminum engine....or any other type of problem that's neglected/ignored.

 

Unfortunately for me that is exactly what the guy did who sold it to me...I just didn't find out about the overheating problem until later.

 

i would have probably just bought a long block VQ and swapped it out and parted out the motor with the blown head gasket to help fund the long block..

but then again i have the know how/tools/space to do something like that

 

Tools - yes
Know how - yes
Space - yes
TIME - HECK NO

Work and school full time with a wife and child. Sell it (made a profit) and buy something else.

 

Smart move for your situation....Too bad you did business with a liar the first time ...he'll get his!

 

Depends if he informed the new buyer about the issue at hand.