On a 5.0 Mustang I had, I noticed excess crankcase pressure, but no other symptoms. Compression test was very good on all cylinders, normal operating temps, everything looked good. I finally did a leakdown test, and one cylinder was leaking 23%, and was because of a head gasket.

 

It is a head gasket.....Believe me I have seen a few.

 

We have received Many calls about this issue from customers who had their engines built from other vendors.(Not trying to cause troulbe just stating the facts) And without a doubt its the HEAD GASKETS! We have many trucks pushing 25# and upwards. that don't push any coolant out the cap.. this is something we learned along the way..there's alot more to it when we start turning these trucks up......JL

 

If the symptoms only appear at WOT, how can a compression test indicate the conditions inside the cylinder? Momentarily lifting a head under high boost conditions is not an unknown phenomena. Listen to Chris and Johnny.

There's always a price to pay to be a leader and you're sure paying your share. Good Luck.

Oh, BTW, maybe your L-kharma would change for the better if you quit blaming REM for everything. Just a thought.

 

A a car dealer,i have seen it all and what you have is either a blown head gasket or a cracked head period.Since there are quite a few people who have had this problem and it was the head gasket.I would bet that is your problem.USUALLY when I see this problem with cars,Its a cracked head so you should be happy its not that!

 

You are probably having a head lift under high boost. Mine did that and I retorqued the heads and it went away for awhile. When it happened with anything over 16psi boost I took the engine out and installed new gaskets.

Me on dyno blowing fluid out of radiator cap.

If you would have done a search there are several posts which cover this.

 

Hey Guys-


Like others, my head gaskets definitely caused this. Hasn't happened since I replaced them.

Be careful with your intake set-up. Having the filter exposed right by the cap could lead to your motor injesting that coolant as it sprays out.

this happed to me, at WOT, and led to the immediate failure of spark plugs.

Which is another thing that hasn't happened since this problem was squared away.

If it were my truck, I'd replace 'em right away. Assuming the cap passes the pressure test.


-Andy

 

Good talking with you today Pete. Just lemme knwo when your ready....

Justin@JDM

 

I can't beleive that your built motor wasn't decked! Even if its a new block, I'd definately consider rebuilding this winter with a block thats machined properly. Also may want to check the tune, since detonation will cause blown headgaskets.

Jagged Edge melted all 8 plugs, burned all 16 valves and blew both the headgaskets at L fest due to detonation. Good luck.

 

 

Definitely a head gasket. I'd recommend the new Ford head gaskets. There is a newer part number, there's a thread on it you can find in the search.

 

Very True about detonation, it will wreck things fast. Im just curious as to how you plan on correcting the Cam timing if you deck the block and resurface the heads ?

 

With the minor amount of material removed the cam timing wouldn't be changed very much at all. Less than a degree in all but the most extreme situations. The tensioners allow for chain stretch/wear adjustment well beyond what this would cause.

Eric

 

Maybe I am missing something here, but how can someone say that a big HP motor is causing more "cavitation" from the water pump? The water pump always spins at the same speed compared to the crank. It might come up to max RPM a little faster with more HP, but never more water pump RPM's unless the pulley is changed, or the motor RPM's are increased.

 

LOOKS LIKE #5....135 PSI ALL OTHERS AT 151+ PSI