My motor has a riddle for ya's...head issues...

[merc91]

alright i did a gt40P head swap amongst many other things to the motor and it goes like a raped ape now but has a problem.

Exhaust gas leaks into my coolant system, but no antifreeze gets into the oil or gets burned, the displaced coolent just goes into the overflow tank and doesn't return do to exhaust gas taking up space.

I had this issue and took the heads off and no gasket problems, bolt torqing was correct at 80ft/lbs now, 75 the first build, gaskets were on correct and the shop gave the heads a check for warping which turned up good also. So i put it all back together again and still have the same damn problem. I put in a bottle of stop leak to keep the coolent displacement at 1" per hour of driving for now. I did a very close visual inspection for cracks and found non but i did no magnafluxing. Compression check turned up good at 130psi on all cylinders, and no steam cleaning in any cylinders. LOPO engine was perfect before build, besides the 150 hp.

so if you guys can figure out what could be doing this tell me your ideas.

thanks, andy

[marquisman]

i wish i could give you advice but, iv never experienced somethin like that

[88grandmarq]

how exactly did you determine there is exhaust gas getting into the cooling system?

:confused:

[grandpaslincoln]

That's what I was thinking too. When the coolant system dumps coolant into the recovery tank it doesn't mean it's going to suck all of it back in when the system cools. It probably appears as though none of the coolant is being sucked back in but it is. If all of it were sucked back in then it would draw air too, which is what the tank is there to prevent in the first place.

[P72Ford]

Maybe he did a block test. You know, where you use the solution, and if it changes color, you have combustion entering the cooling system.

Its really the best way to determine if combustion is entering the cooling system.

But (like was mentioned), just because the coolant fills the overflow and doesn't return to the engine, that doesn't necessarily mean it is being displaced by exhaust gasses.

[marquisman]

do you at all smell coolant in the exhaust?

[1990LTD]

no white smoke?

[merc91]

When I pop off the rad cap after the engine has fully cooled, their's an inch or 2 of coolant missing and the air occupying that space reeks like exhaust. And when the engine is idling with the cap off thier are pulses pushing up the coolant until some bubbles make thier way out that also smell like exhaust. And after running the car, I can wait a half hour and then crack the cap open and exhaust smelling air pressure comes out.

Say my overflow tank is filled to the full cold mark, well i'll drive it for 30 minutes and then it will be up close to the top or even pissing out the top, then the engine cools and pulls an inch back out of the overflow but I still gained 5 inches of coolent in thier. I take it for another 30 minute drive and i'm shooting coolant out of my overflow tank in no time and let the engine cool and look in the rad and i'm missing 4 inches of coolant but lots of exausty air.

...but the killer is thiers no coolant smell in the exhaust, and no white smoke.

I don't know if thiers a hairline crack or a small low spot in the head that can hold back the 16psi of coolent pressure one way, but let through the air at combustion pressures.

[gadget73]

Have those heads been ported? Its supposed to be very easy to get from the exhaust ports to the water jackets on a P head if not careful. Could be a crack in one of the heads.

[Neal 97 250]

I agree, Gasket or crack in the head. It is interesting the exhaust smell but no coolant in exhaust. Did you have the heads checked for warpage when you did the porting?

[88grandmarq]

what EGR spacer are you using and what EGR gaskets do you have? are the coolant lines to EGR spacer hooked up ?

[88grandmarq]

2 simple tests you can do...

1st, pressure test the cooling system see if it holds pressure.

2nd do a cylinder leak down test, if there is a crack in one or more of the ports, this will show it.

[merc91]

cooling system pressure test showed up very good, the heads were not hogged out to bad, the port job was relatively light. EGR spacer coolant lines are not hooked up, and it's a bored out HO spacer to 67mm...but i'm not burning coolant anyways.

Today, after a few days of the stop leak in their, it 99% stopped the exhaust leaking into my coolant system.

I will get a leak down test done if and when it starts leaking again.

[86VickyLX]

stop leak. Big no no! Get your heads magnafluxed, it sounds like there's a crack somewhere.

[merc91]

more then likely a crack, it sucks having this problem with my daily driver to college and work so it was pretty much a no-choicer to give the stop leak a whirl since i couldn't go more than 15 minutes of driving before all my coolant was pushed out and a big overheat.

Tomorrow I'm going to re-torque the long head bolts and hopefully i'll be able to get something on them and if not i'll have to get something sorted out and get the heads magnafluxed i guess.

[86VickyLX]

more then likely a crack, it sucks having this problem with my daily driver to college and work so it was pretty much a no-choicer to give the stop leak a whirl since i couldn't go more than 15 minutes of driving before all my coolant was pushed out and a big overheat.

Tomorrow I'm going to re-torque the long head bolts and hopefully i'll be able to get something on them and if not i'll have to get something sorted out and get the heads magnafluxed i guess.
The torque on those ARP head bolts are like 70 or 75 ftlbs iirc. Torquing them more isn't going to compensate for a crack.

[merc91]

I had originally torqued the long bolts down to 75 with the moly paste they supplied and I was hoping to see that they loosened a little after heat cycles but no dice, all clicked at 75 lbs still so the heads are comming off in 2 weeks, and while i'm at it I might try my luck with the comp xe-258 cam and some new valve springs.

[86VickyLX]

I had originally torqued the long bolts down to 75 with the moly paste they supplied and I was hoping to see that they loosened a little after heat cycles but no dice, all clicked at 75 lbs still so the heads are comming off in 2 weeks, and while i'm at it I might try my luck with the comp xe-258 cam and some new valve springs.
I know that Zoomie somewhere is spl00ging in his pants from that cam selection.

[merc91]

My new ported GT40P heads and comp springs will be in next week allong with the comp xe258 and ford racing 1.6 roller rockers. Throwing it all on that week.

[1990LTD]

bought new heads?

[merc91]

yeh new heads, I've had enough screwing around swapping head gaskets and doing rebuilds trying to find the problem which is probly a crack so i'm buying a set from promar engine so i'm guarenteed a great set of problem free heads to slap on. Could be the current "P" heads just need re-surfacing even though they checked out fine for warpage, or a small crack repair...if a shop can make them check out i'll sell em I guess with my 1.7 RR's.

I have seen enough hype about this 258XE cam so I guess someone's gotta see how it works or fits with the PTV clearances... So i'm going to give it a whirl.

[1990LTD]

if a shop can work some magic and guarantee they'll work....you got a sale.