Pulling the head on a 2.3L duratec

[yellowss7]

I've been chasing a coolant pressurization issue for about a year now on Orange. It only occurs after running hard on track. I've had it idle for over an hour at 195F and there was no pressurization of the coolant system using EVANS coolant. However, on track, while the coolant temp stays steady at 195-200F during a 25 minute session, I've had the coolant puke or burp from the expansion tank, and I then see a significant stream of air/gas bubbles rising up from the bottom hose on the expansion tank into the tank. I've done at least 15 exhaust gas tests, for exhaust gas in the coolant, all negative. Car runs great, but obviously something is not right.

 

I've replaced the radiator, water pump, idler belt tensioner, thermostat, moved the expansion tank up to the highest point possible, installed a few one way valves on the small bleed lines, installed a bleed line from the radiator to the expansion tank, and switched to Evans coolant, which has a 365F boiling temp. And Still I'm getting pressure/bubbles in the cooling system after running on track. So even though the exhaust gas tests are negative, I'm at the point that I'm going to pull the head to see what's going on there.

 

My question is, "Can the head be pulled with the motor in place, or is it an engine out job"? It is an SV with the dry sump tank infront of the timing cover. Tom

[FE07]

Tom,

If you remember, I had the same problem at NJMP. Changed the overflow cap, checked all the lines/clamps, thought maybe the head gasket was bad etc...

 

Long and short of it- I simply removed some fluid from the overflow and problem has resolved. I run with about 1/8 of the tank full. No leakage, antifreeze smell and car runs fine temp. wise.

 

If you have'nt already tried that, I'd certainly do it before I'd pull the head.

 

Jim A.

[xcarguy]

Tom,

 

You and I have had several conversations about this. Jim beat me to the punch...what psi cap are you running?

[yellowss7]

Tom,

 

You and I have had several conversations about this. Jim beat me to the punch...what psi cap are you running?

 

Shane, I started with a 16 psi, moved up to a 20 psi and now have a 29 psi cap on.

[yellowss7]

Jim, I've run it 3/4 full, 1/2 full, at the Max Fill line, at the MIN fill line, Below the Min fill line. Pukes when at Max or above, but still builds pressure and gets the bubbles when run hard on track. I've checked all the clamps, hoses and as I said, replaced every cooling system component. Coolant temp is fine on track now, but the air/gas displacing the coolant can't be good.

 

If you have'nt already tried that, I'd certainly do it before I'd pull the head.

 

Jim A.

[Dave W]

Here is another possibility. It could be water pump cavitation at high RPM. The pump is turning to may revs. Try a larger pulley or cut down the vanes and reducing inlet /out cooling system restrictions to/from the motor. May even require addition plumping. Dave W

[yellowss7]

Here is another possibility. It could be water pump cavitation at high RPM. The pump is turning to may revs. Try a larger pulley or cut down the vanes and reducing inlet /out cooling system restrictions to/from the motor. May even require addition plumping. Dave W

 

This is a Cosworth built motor, and does have the cosworth larger pulley on the water pump. I know SBD in the UK only use an electric water pump, but I have not got to that yet. Keep the ideas coming. Thanks Tom

[slomove]

Ever tried a cylinder leakdown test (will bubble out of the coolant filler if a leak is there) or a cold pressurization of the cooling system (

 

Another idea.... many coolant caps come in 2 versions. One that has the inner rubber seal spring loaded (non-vented) and one that has it loose (vented). You can see the rubber disc of the vented one wiggle when you shake it. This will not allow pressure buildup with slowly expanding coolant because it leaks readily out to the overflow. It will only close and start pressurizing when there is a steam burst or rapidly expanding coolant. For my Raceline water rail only the non-vented one works properly but it MUST be installed at the very top of the cooling system.

Edited September 8, 2015 by slomove

[xcarguy]

I think old yeller is jealous...maybe dumping something in the radiator at night while you're asleep. :jester:

[yellowss7]

Have had the leakdown test and done and no bubbles in the coolant tank. Just got back from the mechanics and next suggestion is to do a session on track holding the rpms to 5000 or less to rule out the water pump cavitation. So I'll try that next I guess.

[Croc]

Just got back from the mechanics and next suggestion is to do a session on track holding the rpms to 5000 or less to rule out the water pump cavitation. So I'll try that next I guess.

 

Easy - you do that all sessions :troll:

[yellowss7]

Just waiting for a point by from you. :driving::smash:

[FE07]

Tom,

I assume (perhaps incorrectly) that you're pulling the head to check the head gasket. Sounds like you've done multiple tests to confirm it's not the head gasket, no antifreeze in the oil or exhaust, leakdown OK, temps OK. So............ I'd say don't worry about it. Of course-my Zetec would probably cost about 1/10 the price of your Cossie to replace!! Sounds like you've done your 'due dilligence'.

 

Just my 2 cents,

 

Jim

[yellowss7]

Correct Jim. I've had the oil checked, done at least 15 exhaust gas tests. Spent a good bit on replacing all of the cooling system parts and Although the coolant temp issue is now good, I still have it puking coolant and pressurizing when at track RPMs. Head gasket or an electric water pump are the only things left that I can think of.

[m wirth]

One more idea, have you used either the Lisle fill funnel or the Airlift, http://www.uview.com/index.cfm?DSP=ProductDetail&startrow=1&CategoryID=1330&SubCatID=0&ProductID=5120&pagepath=Products/Cooling&id=45700 to purge all air pockets, I had a problem motor that would over heat from air lock and even damaged my heater core, the funnel fixed it, and the Airlift is suppose to be better.

 

mike

[yellowss7]

Did use the airlift originally when I first took out the thermostat, but when I replaced the thermostat, the water pump and the radiator I have not. I have put the car on a slope or winched it up backwards on my trailer ramp and let it idle with the cap off, and revved it occasionally for several days in a row until all bubbles stopped coming out of the small 1/4 inch hoses into the expansion tank. Pretty confident that that has been a complete bleed of the system. The fact that the car will now idle for over an hour and hold steady at 195F with no pressure build up is a big plus now. Originally, it wouldn't last long idling and would hit 220F before I'd shut it down.

[yellowss7]

Update. Over the last 3 trackdays I decided to run at set Max revs during each session and see what the results were. 3 weeks ago, I started the first session at 3000 rpm Max which I held the car at that rpm for the whole 25 minutes session. Coolant temp stayed at 190F, no bubbles rose in to the expansion tank when I winched the car up backwards on to the trailer ramp. No Puking or Burping. For each of the next 5 sessions I ramped up the max rpms by 500 rpm per session. I finished the 6th and last session of the day at 5500 rpm max, which again I held it at those revs for the entire 25 minute session. No Bubbles, no Puking, No Burping, no rise in the coolant tank other than an inch or so, and the next day when I opened the cap on the tank there was Zero pressure build up and the coolant level was at the max line where it started the day before.

 

The next trackday, I started out with 6000 rpms as my max level and this time at the end of 25 minutes on track, there were a few bubbles rising into the tank when I winched the car up the ramp. No Puking or Burping, Coolant level rose slightly but not significantly. Coolant temp stayed at 190F the whole session. Same results at 6500 rpm. I did get significantly more bubbles at the 7000 rpm max , and the coolant level did rise to about the 3/4 full level in the tank. No Puking, No burping, Coolant temp again held Steady at 191-192F. very slight pressure venting when I opened the cap the next day. Coolant level back to the Max level.

 

Only other variable I eliminated during those two trackday tests was not to take the left hand turns at any speed. I slowed down before the left handers to eliminate the possibility of the coolant sloshing in the tank under acceleration in the left handers.

 

On the final session of that day, I held the revs to 5000 rpm and ran hard in the left handers and the result was No bubbles and no puking, Temp steady at 190F.

 

Last week, I ran the day, running hard but keeping the max revs around 6000-6200 rpm. Had some bubbles when winched up the ramp, No Puking, No Burping, and coolant temp was rock steady at 190F.

 

As I said before, I had replaced the radiator, (triple pass) thermostat, Water pump, Belt tensioner, Moved the coolant tank to the top of the bulkhead, installed a bleeder from the radiator to the expansion tank and installed a couple of one way valves in the small 1/4 hoses coming from the head and radiator into the top of the expansion tank. I've done a few more exhaust gas tests to see if there is any exhaust gas present in the coolant tank when running/idling, but they are still all negative. This has been going on since last year. I've seem to solved the temp issue with moving the header tank and the new radiator and other mods, but still getting the bubbles and some pressurization at higher revs. Car runs fine otherwise, and I've had the oil tested and no sign of coolant or other issues in it.

 

Any other thoughts before I pull the head? :banghead::banghead::banghead: Tom

Edited October 14, 2015 by yellowss7
spelling correction