Well I finally got around to doing a leakdown test this evening on my car. I have had a few days that my overflow bottle has wigged out, going high and then low and it has seemed I was getting air in the cooling system and then the system would burp it out drivi ng with the heater on.

Here were my numbers:

1) 15%
2) 15%
3) 15%
4) 10%

Numbers dont seem too bad, but there was one thing I noticed... When I had the tester on number one and was figuring out how to use the gauge, I had the radiator cap off and it started to spill over. This would lead me to believe that the head gasket is leaking air from the cylinder into the cooling system. I also had a friend do the exact same thing to his car with a freshly installed Inline pro gasket and it also had the coolant spilling out when cylinder number one was pressurized. I had to leave it pressurized for 45 seconds to a minute before I would notice the coolant..

This leaves me to believe that other may have the same problem and not know..
Anyone else want to check their car and see if they get the same results?
We have plans to test a stock headgasket car later this week as a control.

 

When I was having issues and performed a leakdown test, all cylinders were less than 5% and I had NO bubbles in the radiator. I do have a stock head gasket though on my low compression motor.

 

Thats not good man.

 

I did have some slight scores in a couple of the cylinders when the head was off so I know there is a little blow by from them.. I did still make 457 hp with them like that however.

The spilling over coolant is the sucky part, because thats a definite headgasket IMO.. No bubbles coming out, just the coolant rising out the filler neck and slowly spilling over.

 

So has anyone else done this test and more importantly let each cylinder sit pressurized with the radiator cap off?


Now I got to make some decisions as far as what I want to do to resolve this, which is mainly driven by how much money I want to spend and how much power I want out of the car.

 

Well I have to options at this point:

1) Pull the head, get it decked and install the Cosworth 1.1mm gasket. ($600)
2) Havethe motor yanked and a built bottom end installed with OEM gasket. ($4k)

I'm starting to lean towards number 2..

 

how much pressure were you putting to it when you tested it?

 

My compressor was at 80 psi or so but the pressure gauge on the leak down tester at zero set was only 25-30 psi or so if I remember correctly.

 

did you get the positioning of the TDC for each of the pistons exactly correct before you did the test?

 

Yes, I had the valve cover off so I could see the lobes.
The water was coming on number one and it was easy to line number one with the timing mark on the crank pulley.