I think i might have a leaking cylinder as it seems that my coolant system is being pressurized and im losing boost for no reason.

My tuner says this is becuase air being compressed in the cyl. chamber is escaping into the coolant channel and pressurizing the coolant system/dropping boost.

My coolant is a little dark by it doesnt necessarily look like its mixing with oil. Also my oil is crystal clean.

i am running a copper headgasket.

Do you think his diagnosis is correct? Could i compression test to check for the leak or will only a leakdown test show it?

 

help

 

You should probably leak down test the car that will tell ya whats letting loose in the system.

 

I recently had problems with my coolant system getting pressurised. I wasn't losing boost tho, it was just forcing the contents of the radiator out all over the engine bay.

Looks like the problem was the head bolts had not been torqued down properly so it was leaking through the head gasket.

By the way a leakdown test did not show anything wrong, as it was only under boost that it happened. We did the head gasket as a last resort after bleeding/flushing the coolant system, changing the radiator etc. Hopefully all ok now

 

Have you changed the head bolts? My B series was lifting the head on boost so swapped to ARP stids and the problem was solved. I think it also a common problem on alot of D series

 

After you drive check and see if the radiator hoses are really tight (very hard to squeze)

 

the engine is built- i didint build it though so im not sure if the head bolts are ARP or something else.

The headgasket is copper.

I am assuming the head is ligtin up a little under boost cause the system is being pressurized only under boost. I cant check the lines cause the car is back in MD, but the coolant was all getting dumped back into the resevoir, and at somepoints it even overfilled the resevoir and began squirting out.

The system was a lil overfilled so we drained some and it didint gush out anymore but it seemed like the resevoir was still being filled up on boost (just not topping off).

Can a copper headasket be re-used? How hard is it to do a headgasket change on a DOHC? dont you have to remove the camshafts to get to teh head bolts?

thanks for any help

 

before you go tearing **** apart, it you want to make sure its the HG, you can have a shop do a "hydrocarbon" test, they test the chemical contents of your coolant and can tell you if exhaust gas is getting in there.

Like others said, head can lift slightly under extreme pressure and let this happen, yet when you do the comp/leak test, it doesn't show up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike1114 &raquo;</TD></TR><TR><TD CLASS="quote">do a "hydrocarbon" test, they test the chemical contents of your coolant and can tell you if exhaust gas is getting in there.</TD></TR></TABLE>

I think that may be whats happening as the coolant is a little dark like gas is mixing with it- but not dark like oil is mixing with it.

My block has a copper headgasket and is sealed and o-ringed. I am surprised something like this is happening on my setup especially with only 9psi of boost...

Think i should try torquing down the headbolts a few more lbs each? Also, how hard is it to get teh head off of a DOHC if i need to replace the gasket itself? I know the SOHC is easy but for DOHC do you need to remove the camshafts to get to the head bolts?

Thanks for any help! I wanna drive my car!

 

cam caps and cams must be removed.

headbolts are directly beneath the cams. Pretty dep in the head.

 

so i would have to remove all the rocker arms and **** for the cams then as well right

 

also- if i had a hydrocarbon leak (meaning exhuast gas is contacting coolant) wouldnt the coolant heat up a lot more? In turn causing overheating?

I drove around for a good 30min hammering on it all the way out to 8k and the temp still stayed fine...

 

leak could be very minute, not enough to cause overheating.....yet....


No, rocker arms and springs & **** stay in to get to headbolts, you remove, valvecover, Timing belt, vtec oil distribution (if its vtec) cam caps, cams.

Then you have access to the head bolts.

 

Good information..Thanks Mike 1114

 

isnt it really rare for a copper headgasket thats oringed to leak like that?

Any surefire ways to tell the problem? Like leakdown/comp test wont show it if it only occurs in boost right?

who does hydrocarbon testing? would a honda dealership be able to do it?