Sporty-X

Hi,

2 days before i upgrading my heads to LE2 ones, i noticed i had the "low coolant" indicator on in my car.

I thought it was just a sensor related problem so don't paid much attention in it and just make all my work on the engine (changed heads, cam again ...).

After that, i changed the sensor, it stayed same. I didn't thought it was important and si tried to purge better the block ... but discovered the engine was eating water. i made a CO detector test in collant and found i had CO coming in it.

At this point, i though i had mounted my heads not so well (and maybe too quickly) and so take them away again and put some brand new head gaskets.

To avoid having the problem again, i take really my time to put the heads well (torque them in 3 steps) and i really cant beleive having torqued them wrong this time.

My problem is that i have still my engine eating some water and Co test failed again. I noticed also that when engine reach operating temp, i have air coming in the radiator what you can't see if the temperature have not raised.

The engine runs at normal temp.

What can be my problem ? can i have some crack that has devellop in my block ? is there a way to look for such problem ?

can the deck of the block not being also not enough perfect for the gasket to seal well with the head ?

Any advice on my problem would be welcome.

Thx

Pierre



changing

Guest47904

Are you sure all the air is gone from the system?

I like to fill the radiator up with 50/50 and run the engine. When the coolant starts to flow and goes down I fill the radiator until it won't take any more. Then open the coolant bleeders and be sure coolant comes out. continue to fill the radiator until it does not take any more. Cap it off and close it to cool down over night. Next morning top off the overflow and the radiator and take it for a ride.

MarcR94v6

I tried to do that as I have with every other car but this time as soon as I started the car, the coolant boiled up and overflowed. Maybe it was too hot already when I did this. I still managed to bleed the system, though. Maybe I have an electric water pump and don't know it (just bought car).

I would try all over again and make sure the system is bled. I wasn't even sure I did it right the first time to tell you the truth, as I've never done it before and it was a bit of a clumsy mess, but things seem fine, I run cooler than I could have ever dreamed and am good on coolant.

Sporty-X

yes i have no problem bleeding all air from the system since i have the car but here i got a real problem because :

1) the car is eating water (if i travel quite a long way, i really lose water and need to refill)
2) a CO test in coolant shows that there is CO coming in so it is not a leack from coolant at some hose but really coolant going in engine i think

BUBBA

There is a difference between an engine "eating water" and external leak. If your hoses are all good and your temp is ok, I'd consider replacing the radiator cap. Good place to start and at least eliminate a possible cause of boil over and losing coolant. Get the proper cap. JMHO

moparman

I had a disappearing coolant problem on my car. New radiator cap didn't help. Radiator would hold pressure when pumped up, yet a small amount of coolant was disappearing every day. No coolant under car. Then one hot summer day, I drove to get my allergy shots, and when I came back out to the car, there was a pool of coolant under the car. Turns out there was a crack in the plastic radiator tank. The only theory I could come up with was that the crack enlarged when the car was hot, and closed up when it was cold. Finally it gave way.

Guest47904

If you're sure you got all the coolant out from the last test and replaced ALL of it, then the only other answer is head gasket problem.

Sporty-X

hello again,

about radiator cap, i wonder about it got a brand new one and problem is same.

Making a CO test is coolant and showing indicator turning yellow make me beleive there is water passing through clylinders for sure.

About the head gaskets : i changed them twice to be sure and the last time i changed them, we took many precaution on them. A compression test on each cylinders (engine slighly warm) show 15 bars on each cylinders except cylinders 1 and 3 which are 14 what dont seems a problem.

Can i have a crack in the block ???

About heads , there are just new LE2, so i dont beleive it can be a problem from them

Injuneer

The question he was asking was whether you are sure you fully replaced the coolant, before running the second CO test? If you didn't fully drain the block and radiator, is it possible you left some of the CO (or is it CO2?) contaminated coolant in the system?

If you have coolant disappearing, and you repeatedly get combustion gasses in the coolant, the head gasket, a crack in the heads or a crack in the cylinder wall would be possible causes.

Have you done a pressure test of the cooling system?

Sporty-X

oh ok.

Yes, i drain radiator and block the best possible. i've done a pressure test also and it was loosing pressure slowly (but with engine cold)

I'm planning on making a pressure test on each cylinder but as the problem seems to appear when the engine is hot, it would be a little tricky to warm the engine and make the test without burning hands on the headers.

In case i end with a crack in cylinder : is it something that can be repaired well ? or will i have to go with another block ?

Guest47904

Stop relying on a CO test of the coolant. Use a coolant system pressure test as mentioned above AND a leak down test on the cylinder. If the coolant is getting into the combustion chamber, either one of those tests will find it.

It's important to find the "leak" while using either test. Keep in mind what is happening and where to look. In the case of the leak down test, you are using air in the cylinder. This can be putting bubbles into the coolant system IF the leak is of that type. The coolant system pressure test would have the effect of putting coolant either in the crankcase or in the cylinder. Look at the oil or check the cylinders after pressure testing by cranking the engine over with the plugs OUT. If there is coolant in a cylinder, cranking it over will shoot the coolant out the plug whole. Don't forget you may be leaking coolant externally and not in the engine.

Keep in mind also, if your problem is of this nature, you should have other symptoms as well. When you analyze all the symptoms, it will tell you where the problem is.