I have been having a small amount of coolant blowing out the cap and today I was able to do a pressure test. While driving down the highway it gets up to 14-15 psi and stays there. Running the srl tune with studs and the hated black onyx gaskets. Was wondering if this was normal operating pressure or do I have the start of a gasket leak?

 

Could possibly be HG's...do you still have the EGR cooler?

 

No its gone.

 

You are right there at max pressure. Cap is rated at 16psi. Might try a new cap. Check sealing surface on bottle. I think most trucks stay around 7-9psi so you have somthing going on.

 

Depending on your alt, coolant brand, and temp that pressure is OK.

Caps are 10 bucks at autozone, clean the bottle and replace the cap. that may help.

If you can test the system pressure under heavy load that is what you are looking for.

 

Sounds like a HG going, I had this condition and just replaced both heads due to small dents in the heads mech. didn't feel comfortable machining out -too deep.

No cross fluid contamination, minor puking and Tea Kettle.

Good Luck, YMMV.

Denny

 

Yeah I did replace the cap recently but hasn't helped. So it should be around 7-9 cruising down the road. Also should the pressure come down after getting on it?

 

Well, recent posts have referred to the cap being rated at 16psi but I found this statement in the tech folder "Degas cap rated for 12 - 18 psig. Over 18 psig indicates possible headgasket leak." so it looks like there's some tolerance. As you likely know, the BO gaskets seem to have a higher failure rate than the factory gaskets. Might try backing off the tunes and re checking. It depends on how long you stay in it but generally the pressure will go up when you romp on it and will continue to increase for a short while after you get off it and then decrease slowly.

 

Thanks for the replies everyone. I put my truck back to stock and tried another gauge. I still got the same readings. Looks like ill be doing it again the right way.

 

Man, there's a lot of broke trucks on our forum lately! Are you going to do theses yourself?

 

No, I'm going to use the shop I used before. I don't really have the time to try to tackle it myself.