turbo coolant and overflow
05-01-2004, 02:56 PM
#31
Instructor
Thread Starter
Back from the track... same problem.
I ran the exp tank overflow pipe into a catch bottle, drove 2 or 3 laps (Lime Rock) and came into the pits. A couple of pints in the catch bottle. Temperature normal.
Brian S.: You said you had the same symptom, and it turned out to be the radiator. Was your car running hot, or was the temperature gauge reading normal? The rad is just about the only thing I haven't changed yet, and its the original '86.
Jon.
I ran the exp tank overflow pipe into a catch bottle, drove 2 or 3 laps (Lime Rock) and came into the pits. A couple of pints in the catch bottle. Temperature normal.
Brian S.: You said you had the same symptom, and it turned out to be the radiator. Was your car running hot, or was the temperature gauge reading normal? The rad is just about the only thing I haven't changed yet, and its the original '86.
Jon.
05-01-2004, 03:35 PM
#32
Drifting
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One more thing to check.
Could it be that the OIL lines to the turbo are restricted and not providing the cooling that the turbo needs. This could cause the turbo to become so hot that the turbo water pump can't keep up with the heat and causes the boil over. Is there an easy way to check this?
I'm grasping at straws......
Could it be that the OIL lines to the turbo are restricted and not providing the cooling that the turbo needs. This could cause the turbo to become so hot that the turbo water pump can't keep up with the heat and causes the boil over. Is there an easy way to check this?
I'm grasping at straws......
05-02-2004, 02:14 AM
#34
Three Wheelin'
This is EXACTLY what I'm dealing with on my car. I've changed the headgasket needlessly just to try and solve this. I'm glad I'm not the only one who's dealing with this, but I won't be able to dig into it for another week or so.
I'm very interested in following this thread.
I'm very interested in following this thread.
05-02-2004, 11:04 AM
#35
Instructor
Thread Starter
I performed the test for hydrocarbons (combustion gasses) in the coolant. This is a test kit where you bubble air/gas out of the expansion tank thru a vial of blue liquid. The liquid turns yellow if there are hydrocarbons, which would mean a cylinder leak.
Starting from a freshly bled system, if I let the car idle and warm up, the test is negative.
I then went out for spirited 5 mile drive, hitting max boost in 2nd and 3rd as much as possible. Got a few ounces in the catch bottle. Temp gauge is at the low/normal mark. The output hose from the water pump to the radiator is very hard. This time the test was positive.
In the process of doing this test however, the exp tank eventually overflows as the pressure is relieved. I re-fill and bleed.
This time I go out for the same 5 mile drive, but take it leisurely. Nothing in he catch bottle, the output hose from the water pump to the radiator is soft, hydrocarbon test negative.
Go back out and get on boost again. Same as before - couple of ounces in the catch bottle, hose is hard, hydrocarbon test positive.
Before I go and swap motors, is there ANY other place this mixing under boost could happen other than the block? Is there any path within the turbocharger that would let exhaust pressure into the coolant? I'm grasping!
Jon.
Starting from a freshly bled system, if I let the car idle and warm up, the test is negative.
I then went out for spirited 5 mile drive, hitting max boost in 2nd and 3rd as much as possible. Got a few ounces in the catch bottle. Temp gauge is at the low/normal mark. The output hose from the water pump to the radiator is very hard. This time the test was positive.
In the process of doing this test however, the exp tank eventually overflows as the pressure is relieved. I re-fill and bleed.
This time I go out for the same 5 mile drive, but take it leisurely. Nothing in he catch bottle, the output hose from the water pump to the radiator is soft, hydrocarbon test negative.
Go back out and get on boost again. Same as before - couple of ounces in the catch bottle, hose is hard, hydrocarbon test positive.
Before I go and swap motors, is there ANY other place this mixing under boost could happen other than the block? Is there any path within the turbocharger that would let exhaust pressure into the coolant? I'm grasping!
Jon.
05-02-2004, 03:02 PM
#36
Ugh. Jon, everytime I read a new post my heart sinks a little more...I've been chasing the same problem but I'm still on the beginning stages of replacing all the things you have done already so everytime something doesn't work for you it makes me sad...but let me ask this...I know you totally redid the head and headgasket, as well as using new racewears, but have you re-torqued the head to make sure it isn't lifting a little bit? I mean, wouldn't there be at least a little seepage if it was a cracked head or block when you pressurized the coolant for like 15 minutes?
05-02-2004, 03:59 PM
#37
Three Wheelin'
That makes 3 of us with the exact same problem. Just as a point of reference, heres what I've replaced:
Headgasket (head was leveled and valve job when it was off)
Coolant tank
Tank cap
Another thing to note:
The turbo has some blow-by. I'll go through a qt of oil after a period of hard driving.
Also, there's some kind of gunk that accumulates on the inside of the coolant tank (like grease or soemthing) but both coolant and oil are completely clean (no mixing)
Headgasket (head was leveled and valve job when it was off)
Coolant tank
Tank cap
Another thing to note:
The turbo has some blow-by. I'll go through a qt of oil after a period of hard driving.
Also, there's some kind of gunk that accumulates on the inside of the coolant tank (like grease or soemthing) but both coolant and oil are completely clean (no mixing)
05-02-2004, 04:13 PM
#38
My only real problem to note is that every once in a while (and it doesn't seem to be related specifically to heavy boost driving) it will overflow...there are days that I can run for 2 hours on the highway and run full boost regularly (i.e. seeing 15psi for good periods of time) and no problem, but some days, I'll run 15 minutes or 20 minutes (happened yesterday even) with moderate and occasional heavy boost and park and suddenly I have a green puddle under the overflow. I've already had head with resurfacing and leveling, as well as new HG with widefire. Car will occasionally run up to the 2nd mark on the temp gauge, but that seems to be only at first when I start driving and the car is warming up, and as soon as the fans come on high and the t-stat opens, it is fine for the rest of the drive once it comes down. never gets into the red, and usually runs barely above the 1st mark. Sometimes it will go 3 weeks without an overflow, sometimes it happens after 2 days. Generally I just keep a big-a$$ bottle of water in the back seat and re-fill as necessary and have yet to see a 'problem' other than the occasional overflow. New expansion tank and cap are waiting for a good day to be installed but I'm not overly optimistic after reading this thread...
05-02-2004, 04:52 PM
#39
Drifting
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Has everyone that is having this problem seen it happen??
I've watched it happen a few times and (at least mine) it's defiently from the turbo being to hot and boiling over. The temp sensor in my turbo is toast, as the water pump only runs for the min 30sec, and if I ground the sensor wire it will continue to run. Hopefully it will fix my problem when I replace it.
When your guy's overflowing occurs is it while the turbo water pump is running or after everything shuts down (fans/pump)?
Could this simply be an intermitten wiring problem causing the turbo water pump not to run when it should?
I've watched it happen a few times and (at least mine) it's defiently from the turbo being to hot and boiling over. The temp sensor in my turbo is toast, as the water pump only runs for the min 30sec, and if I ground the sensor wire it will continue to run. Hopefully it will fix my problem when I replace it.
When your guy's overflowing occurs is it while the turbo water pump is running or after everything shuts down (fans/pump)?
Could this simply be an intermitten wiring problem causing the turbo water pump not to run when it should?
05-02-2004, 04:58 PM
#40
Instructor
Thread Starter
MachSchnell- Yes, I've retorqued the studs after running the engine up to temperature. FWIW, the nuts didn't move.
So it sounds like more people have this problem. Hard to believe we all have warped block decks or worse, cracked cylinders, but I'm about out of alternatives.
I've got another motor sitting here, but the thought of swapping without first KNOWING what the cause is, is not very appealing. If the cause isn't in the block or the head, I'll still have the problem.
Still pondering, for now.
Jon.
So it sounds like more people have this problem. Hard to believe we all have warped block decks or worse, cracked cylinders, but I'm about out of alternatives.
I've got another motor sitting here, but the thought of swapping without first KNOWING what the cause is, is not very appealing. If the cause isn't in the block or the head, I'll still have the problem.
Still pondering, for now.
Jon.
05-02-2004, 05:54 PM
#41
Nordschleife Master
Originally posted by Jason_86_951
The temp sensor in my turbo is toast, as the water pump only runs for the min 30sec, and if I ground the sensor wire it will continue to run. Hopefully it will fix my problem when I replace it.
The temp sensor in my turbo is toast, as the water pump only runs for the min 30sec, and if I ground the sensor wire it will continue to run. Hopefully it will fix my problem when I replace it.
05-02-2004, 06:52 PM
#42
Three Wheelin'
My problem has happened usually when I can't see it.
The coolant is actually coming out of the top of the cap, bypassing the overflow line completely and only when I'm under very high load. This leads me to believe that it's caused by a very dramatic increase in pressure in the tank when the car is under heavy boost.
I'm running a K26/8 (Turbo S) in my car, and I'll be tearing things apart soon to see whats happening. I've been running at a decreased coolant level for a while (it only overflows to a certain point, then it doesn't leak anymore) and hopefully the turbo isn't too f*cked. What turbos are you guys running in your cars?
The coolant is actually coming out of the top of the cap, bypassing the overflow line completely and only when I'm under very high load. This leads me to believe that it's caused by a very dramatic increase in pressure in the tank when the car is under heavy boost.
I'm running a K26/8 (Turbo S) in my car, and I'll be tearing things apart soon to see whats happening. I've been running at a decreased coolant level for a while (it only overflows to a certain point, then it doesn't leak anymore) and hopefully the turbo isn't too f*cked. What turbos are you guys running in your cars?
05-02-2004, 08:41 PM
#43
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All -
Mine tosses some coolant now and then as well. Like Nicks, mine will dump coolant to a point, then it will stay there. I'm not too sure where my coolant is going since I have not seen any puddles, and the coolant/HC test comes up clear each time. My plugs all read fine, so I can be pretty sure that coolant is not making it's way into the cylinders. I have not tried a catch can to check for overflow at speed, so that is still a possibility.
The only part of my cooling system that has not been replaced is the radiator. Most of us see overflow after we've run the car a bit, and most likely, we'll see overflow right after the T-stat makes it's cycle. When the hot water from the run makes it to the radiator, it sits long enough to create some extra pressue and backs up into the coolant tank. Since our OEM radiators have some significant corrosion by now, it cannot remove the heat fast enough to keep the pressure in control.
Am I babbling or making sense?
Mine tosses some coolant now and then as well. Like Nicks, mine will dump coolant to a point, then it will stay there. I'm not too sure where my coolant is going since I have not seen any puddles, and the coolant/HC test comes up clear each time. My plugs all read fine, so I can be pretty sure that coolant is not making it's way into the cylinders. I have not tried a catch can to check for overflow at speed, so that is still a possibility.
The only part of my cooling system that has not been replaced is the radiator. Most of us see overflow after we've run the car a bit, and most likely, we'll see overflow right after the T-stat makes it's cycle. When the hot water from the run makes it to the radiator, it sits long enough to create some extra pressue and backs up into the coolant tank. Since our OEM radiators have some significant corrosion by now, it cannot remove the heat fast enough to keep the pressure in control.
Am I babbling or making sense?
05-02-2004, 10:55 PM
#44
Instructor
Thread Starter
Perry and others,
If the coolant level is going down, its got to be going somewhere. I don't think that with leakage of the sort we're talking about you'd see symptoms in the cylinders (e.g. washed valve or piston top, or wet plug). Those would be signs of a pretty severe head gasket breach. Since my cooling system only gets pressurized under boost, whatever is leaking takes a lot of pressure to get the gas into the coolant. Our static peak cylinder pressure is 145 psi or so, and I would assume its much higher when the "bang" occurs. The cooling system is only pressurized to 15 psi or so, so its not likely to force its way in to the cylinder unless things are really bad.
Perry, when you did the HC test, did you run the car Real Hard first? That made the difference for me.
What you're saying about the radiator makes sense. Mine's the original too ('86). Just for kicks, I just used a cooling system tester to pressurize the coolant to 22 psi. Caused a leak to occur somewhere in the radiator. Doesn't seem to be hose, but I can't see where its coming from. May have to take the fans out to see. There could be a new rad in my near future. It'll have to come out if I do the engine swap anyway.
Because of the leak, the tester couldn't hold the pressure very long without me having to keep pumping it up. But it was at least 17 psi for a couple of hours. Nothing I could see in the cylinders (as expected).
The notion that this occassional peeing is not uncommon, and that people live with it, is not very comforting, especially for tracked cars. That overflow tube dumps right inside of your left front wheel, the last place you want it when you're at 10/10ths on a right-hander. Not to mention the car in back of you.
The only pressure in the system should be as a result of the increase temperature of the coolant.
BTW, for those that have this overflow issue, what boost level are you people running? I had been running 17psi, and now 15 psi, and didn't make any difference.
Jon.
If the coolant level is going down, its got to be going somewhere. I don't think that with leakage of the sort we're talking about you'd see symptoms in the cylinders (e.g. washed valve or piston top, or wet plug). Those would be signs of a pretty severe head gasket breach. Since my cooling system only gets pressurized under boost, whatever is leaking takes a lot of pressure to get the gas into the coolant. Our static peak cylinder pressure is 145 psi or so, and I would assume its much higher when the "bang" occurs. The cooling system is only pressurized to 15 psi or so, so its not likely to force its way in to the cylinder unless things are really bad.
Perry, when you did the HC test, did you run the car Real Hard first? That made the difference for me.
What you're saying about the radiator makes sense. Mine's the original too ('86). Just for kicks, I just used a cooling system tester to pressurize the coolant to 22 psi. Caused a leak to occur somewhere in the radiator. Doesn't seem to be hose, but I can't see where its coming from. May have to take the fans out to see. There could be a new rad in my near future. It'll have to come out if I do the engine swap anyway.
Because of the leak, the tester couldn't hold the pressure very long without me having to keep pumping it up. But it was at least 17 psi for a couple of hours. Nothing I could see in the cylinders (as expected).
The notion that this occassional peeing is not uncommon, and that people live with it, is not very comforting, especially for tracked cars. That overflow tube dumps right inside of your left front wheel, the last place you want it when you're at 10/10ths on a right-hander. Not to mention the car in back of you.
The only pressure in the system should be as a result of the increase temperature of the coolant.
BTW, for those that have this overflow issue, what boost level are you people running? I had been running 17psi, and now 15 psi, and didn't make any difference.
Jon.
05-02-2004, 11:24 PM
#45
Burning Brakes
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The problem has nothing to do with the turbo boiling. Check my earlier post... leaky combustion chamber.
Remedy: Replace headgasket, torque down (RACEWARE) 20lbs, wait overnight then torque to 50 lbs wait 3 hours... finally torque 80lbs and that's it. No need to retorque.
Remedy: Replace headgasket, torque down (RACEWARE) 20lbs, wait overnight then torque to 50 lbs wait 3 hours... finally torque 80lbs and that's it. No need to retorque.