C-1 smoking redux

[Don Izzo]

Had a friend over yesterday who upon inspection thinks my "smoking problem" is a leaking head gasket or a leak around the water passage in the intake. He noticed that I get a lot of water droplets out of the one tail pipe upon start up, it then goes away for the 15-20 minutes it takes for the temp/ pressure to build in the cooling system and then the water droplets return when I rev the motor. He thinks the smoke smells more like coolant or steam and less like oil. I am going to run the car with the radiator cap off so the system won't build pressure and see if it still "smokes". Then while hot, I am going to pressure test the cooling system through the radiator cap to see if it is losing pressure. As previously stated it only occurs at full operating temp.

When I reinstalled the heads about 100 miles ago, I put a dab of RTV in each corner of the intake gaskets to hold them in place while installing the intake, I may have let the RTV set up to long ( a few hours) and this may be where the root of my problem lies. Comments?

Is there anyway to tell if the intake gsket has failed rather than the head gasket or should I r/r both?

Don

[Terry F.]

Re: C-1 smoking redux

Waiting a couple hours on the RTV is too long because it will essentially set up. Whether it is causing your problems, I don't know. Terry

[Dave Suesz]

Which side

do the lot of water droplets comed out? If the left, and you have a functioning bypass valve, this is normal.

[Jimmy J.]

Re: C-1 smoking redux

Don, is the smoke white or black? Jimmy

[Don Izzo]

Re: C-1 smoking redux

I do have a functioning heat riser valve. The smoke is on the right side same as the valve. The smoke has a very light blue tinge . The spark plugs show NO oil at all leading my friend further to believe it is coolant. He felt the pressure comming out of the two exhaust pipes and says there is a noticable difference (less) on the side that smokes. A Compression test was done with a cold engine (when the smoking does not occur) and found to be in the acceptable range. However I have not done the test while the motor is hot. With the original copper radiator in place, due to the goose neck filler it is not possible to look into the top tank and see if there are any air bubbles appearing while the engine is running.

Don

[Joe L.]

Re: C-1 smoking redux

Don-----

If coolant is leaking from any source into the combustion chamber, then there will also usually be leaking of exhaust gas into the coolant. You can run a block test on the coolant to determine if any combustion products are found in the coolant. If the test is positive, then you have a leak of combustion gasses into the coolant and you have a problem somewhere. If the test is negative, then you can rest pretty well assured that you have no leakage of combustion products into the coolant and, by extension, you should have no leakage of coolant into the combustion chamber.

A leak from an intake water crossover passage at the gasket will usually not cause any leak of coolant into the combustion chamber. The only way that this could occur would be if the coolant leaked from the crossover passage to one of the intake ports. I've never seen this happen, but I suppose it's possible. Even if the coolant leaks at the inatke gasket, it will usually leak into the valley area (and contaminate the oil). To leak into an intake port, the coolant crossover AND the intake port sections of the gasket have to leak. I've not seen this happen.

[Donald B.]

Re: C-1 smoking redux

Where/how can a person have a "block test" performed on the coolant ??? I suspect I have this problem on my Toyota daily driver.

Thanks,

[don izzo]

Re: C-1 smoking redux

Joe, I topped off the radiator tonight and ran the car. I am now seeing bubbles in the coolant in the filler goose neck. Is this indicative of a bad head gasket or leak elsewhere. I am about to pull the intake and this head in search of why I am having this smoking problem.

I ran the car until hot,and showing smoke in the exhaust, shut it off and hooked up a radiator pressure tester. I put 15 lbs. of pressure in the radiator and monitored the pressure drop. I lost 4 lbs. of pressure in about 15 minutes. Is this significant or indicative of a problem? I did this test when cold and found it took about 45 minutes to drop the 4 lbs. What is a block test where do I get it done?
Don

[Gene M.]

Re: C-1 smoking redux

take the exhaust manifolds off to see what exhaust ports are wet. big blocks have been known to leak at the exhaust valve guides when replaced, small blocks should not have this problem but remote possibility on the intakes.

[Joe L.]

Re: C-1 smoking redux

Don and don------

Personally, I do not consider the observance of bubbles in the filler neck to be anything like a proof-positive test for a combustion gas leak into the coolant. It seems like it should be but, in my experience, it's not. Also, I don't consider the pressure drop to be a good indication, either. Pressure will normally start to drop in a cooling system as soon as the engine is turned off and stops making heat (although, in some cases, there may be a short-lived RISE in temperature and pressure due to heat soak and the cessation of coolant circulation).

In any event, I'd still recommend a block test to positively confirm a combustion gas leak situation. Many automative repair shops can perform this test. Also, the equipment to do it yourself is not too expensive. However, I can't tell you a source at this moment. It's definitely out there, though.

The only problem with this sort of test is, while it can positively confirm a combustion gas leakage condition, it does not tell you what component is at fault. It could be due to a head gasket failure, a cylinder head crack or other failure, or a block crack or other failure.

[Don Izzo]

Re: C-1 smoking redux

Gene, Should I run the engine and then remove the exhaust manifold or can I do it tonigt after the car has sat all day and the engine is cold

Don

[Don Izzo]

Re: C-1 smoking redux

by the way in previous posts I stated that all the plugs where almost abnormally clean and dry. Would I expect to still see wetness in the exhaust ports? Am I looking for water or oil or both?

[Dave Suesz]

Too easy...

any decent repair shop should have a cooling system tester, which is a basically a small hand pump which attaches via a special cap to your radiator. You then pressureze the cooling system and observe the gauge over time to see whether there is a pressure drop, which would indicate a leak. Thses usually have an adapter to check the cap pressure, too.