Overheating Issues

[charger758]

Yesterday I took the car out to an open track day. Running 20min sessions, the car would overheat after about 4 or 5 laps. The radiator cap lifted off and sprayed coolant all over each time. When I refilled, I had the car on level ground while filling with the bleeder cap opened. Also jacked up the front passenger side of the car and did the same until there was no more air coming out. Each time the car did the same thing. Also, even after each refill, I had the engine running with the heat on full blast. At idle the heat would come and go through the vents. I'm pretty sure I got all of the air out but who knows for sure. During normal drives or hard highway pulls the engine doesn't overheat at all.

Today I pulled the waterpump, it is a plastic vein one, but it looks perfect. I'll probably go ahead and replace it with a stewart one. Also pulled my 80C thermostat and threw it in a pot of water and it was full open around 85C. About to look into one of those coolant test kits to see if combustion gasses are getting in and do a compression check on the engine.

Any other ideas?

[black bnr32]

check your ducting around the rad, ie use an underpanel and seal off as many of the gaps around the rad as possible

i'm not sure if its crucial or not, but probably worth a try

[forksports]

I had this exact same problem on my AA s/c E36 M3, it would spray coolant from the reservoir on the track after 20 min or the 2nd session. The car would run fine on the street, or on a long drive. I replaced the tstat to a lower temp tstat, replaced the waterpump, got fluidyne radiator and it didn't help. So I replaced the head gasket + ARP head studs and now the car temp is very stable at the track :)

I hate to say this but most likely your issue is the head gasket, but wouldn't hurt to try replacing the easy parts first.

[agu845]

+1 hg

[charger758]

I just put the car back together and let the engine idle. I still am not getting coolant flow through the heater core. The hg makes sense for the long hard track beatdowns, causing the combustion gasses to be forced into the coolant. If the gasket is so bad that I am getting air into the system causing coolant not to flow through the core, I should see it in a compression check. Wouldn't you think? (I haven't checked the compression yet).

[chikinhed]

I would try a differential cylinder compression check, where compressed air is put into the cylinder, instead of the normal compression check. If you have a very small leak in the head gasket it is most likely to show up with this method.

[BadBoostedBmwM3]

check your HG for sure!

[charger758]

Not sure about the differential pressure check, my air compressor only puts out 130psi or so. I am thinking the cylinder pressures at which the potential hg leakage is happening is more like 1300psi. I did a normal compression test, 190-200psi all across.

The no heat in the cabin at idle still weirds me out. Since refilling the system I haven't taken the engine over idle. I warmed it up once, let it completely cool off, took the cap off and it was still full so I'm thinking I have all the air out. I wonder if that heater valve is partially blocked which is why I am not getting hot coolant into the heater core.

Anyone know what the main purpose of that heater hose valve is?

[BadBoostedBmwM3]

Maybe the heater core (or whatever it is called) is not allowing coolant to pass through anymore.


My old 92 e36 would not produce heat at idle because the thing would not open up. But, anything above idle I had heat.

[charger758]

Right, I am thinking I am chasing 2 things here, 1 being a headgasket and 2 being a partially blocked heater core or a sometimes functioning heater valve.

[billyr3d]

I have been down this road bud. I'm gonna say, I don't think its your headgasket. I'm betting your problem is a few things. For starters, the rad on the Z3 is small (smaller then the m3's) On top of the rad being small, the airflow through it sucked when stock and even more so now that you have the intercooler and possibly an oil cooler obstructing it. Also, your clucth fan has been replaced with a 2 speed spal fan that is dependant on information sent from the temp sensor in the side of the rad.
I replaced the temp sensor with one that turns the fan on sooner...its been awhile, but im gonna say it was 70degrees?? Also, I replaced my thermostat with one from turner.. It's a race one that wasn't listed on their website, but if you are interested I can dig up the part number.

As for the heater core not getting any heat? I think you might just have air in the system. It takes forever to get it out I've found on these cars. In fact, I drove around with a jug of coolant for a week and topped up every so often to make sure that I got it all.

Another thing that I did to reduce engine temps was installing an oil cooler. I can't remember if you had one or not, but that made a substancial difference.

On a side note, and hopefully I am way off with this, but werent you having some running issues? possible detonation? As, I'm sure you know, preignition/detonation can cause overheating too and vise versa.

Keep us posted and good luck!

[charger758]

I have a VSL radiator which is slightly thicker than stock but not much. Also have an 80C thermostat and a temp switch that turns the fan on sooner than the stock one did (I forget the temperature). I have a single speed spal, it is wired to the aux fan wiring in a manner that if either of the two OEM fan outputs are triggered, the fan will run. And yup, I do have an external oil cooler which I had no issues with.

[davidtm5]

:( head gasket for sure . i had the same issues before like that

[black bnr32]

bleed the crap outta that system!

[GT110]

HG .. just experienced similar things.

Put a pressure guage on the coolant and look for pressure build up under boost. It was a dead giveaway in my case.

[charger758]

HG .. just experienced similar things.

Put a pressure guage on the coolant and look for pressure build up under boost. It was a dead giveaway in my case.

Good call, I am trying to come up with a quick and simple way to do this. I am guessing the best place to get a reading is at the upper radiator hose, or does it really not matter?

[LukeG]

Get a cylinder leakage tester. Should be around $50 and it's a nice tool to have. Put 100psi into each cylinder at TDC compression stroke (make sure you have a long breaker bar on the crank bolt to stop engine from rotating) and see if you have coolant bubbling in the expansion tank

[Mad Dog 20/20]

Does the top rad hose remain hard and pressurized overnight? That is pretty definitive of a HG leak.

[EMC]

Josh,
I have a compression tester and a leakdown tester. Feel free to bring the car over and we can run through the compression test in under 30 minutes.

I have an extra heater valve you can try out too if you still have the same issues.

[charger758]

Thanks Eric, I have a leakdown tester. I haven't tried it because like I said the problem only happens after a bad flogging where cylinder pressures are much higher than my air compressor can create.

BTW Eric, remember that time you filmed me flogging the car and it overheated/spewed coolant all over? I blamed it on an air bubble... This is the same issue.

I have an AEM fuel pressure gauge in the car. I am going to try to score a spare AEM sensor and fab something up to connect it to my coolant line so I can monitor the coolant pressure from in the car.

[Neil]

Compression/leak down tests often fail to detect headgasket problems that manifest themselves at the track. Probably worth doing, but I wouldn't rule out a head gasket issue based on the results.

Neil

[GT110]

Thanks Eric, I have a leakdown tester. I haven't tried it because like I said the problem only happens after a bad flogging where cylinder pressures are much higher than my air compressor can create.

BTW Eric, remember that time you filmed me flogging the car and it overheated/spewed coolant all over? I blamed it on an air bubble... This is the same issue.

I have an AEM fuel pressure gauge in the car. I am going to try to score a spare AEM sensor and fab something up to connect it to my coolant line so I can monitor the coolant pressure from in the car.°

Just for refrence,, what gasket are you running.

I was running a Cometic MLS, and the problem did not really surface untill after 30minutes of driving.

[EMC]

°

Just for refrence,, what gasket are you running.

I was running a Cometic MLS, and the problem did not really surface untill after 30minutes of driving.

He's stock compression on original OEM head gasket and bolts.

[agu845]

maybe i missed this part, but was a hydrocarbon in the coolant' test done?

[EMC]

Not yet.

[charger758]

maybe i missed this part, but was a hydrocarbon in the coolant' test done?

I went to all of the local auto parts stores and no one carries the test strips!

I have the coolant saved for later testing.

[GT110]

Im not sure he can do that test with conclusive results. I have a Tee-Kay kit with the colour changing fluid, but it never gave me any results to build on.

Problem was that the pressure in the coolant would not allow me to remove the cap without spilling all the coolant up the resorvoir. So I had to add new coolant.. and by then the test was basically worthless.

Since he only sees this after heavy driving on the track, Im guessing he will have the same problem, fitting the tester to the coolant without the pressure splling the fluid.

[agu845]

pardon my idiocy here, but let me ask a question: if the coolant keeps getting pressurized (manifesting as persistent stiff upper rad hose and/or venting gas way after it's cooled off, 'add coolant' warnings - but without collant leak, etc) then doesnt that essentially mean the HAS TO BE a defect in the hg/head/block allowing combustion gases to get by? what else could cause that?

[GT110]

pardon my idiocy here, but let me ask a question: if the coolant keeps getting pressurized (manifesting as persistent stiff upper rad hose and/or venting gas way after it's cooled off, 'add coolant' warnings - but without collant leak, etc) then doesnt that essentially mean the HAS TO BE a defect in the hg/head/block allowing combustion gases to get by? what else could cause that?

If it would be that consistant, but in my case it was not consistant enough, and it got progressively worse.. In the end, I pulled the head, and found the gasket had said goodbye, but the head was ok.

My guess (before removing the cylinder head) was that head-lift due to not enough clamping force or streached ARP's could have also been the fault..

I dont know if he is getting pressure in the system, or if its just overheating.

[forksports]

If your reservoir bottle pressurizing or if there's air comes out when you open it in the morning then I'm 98% certain is the HG. When I had the HG issue, the car passed the NAPA HG test kit, it was a waste of money IMO.

[charger758]

The hoses are soft the next day, and I would like to get some substantial proof that the hg is toast before I tear into it. It still could just be an air bubble. I am ruling out an undersized cooling system since last year I didn't have any problems with this setup at the track.

Also, I ordered this little gem. The goal is to put an aem sensor in there and run it to my fuel pressure guage and wire in a switch to go from fuel pressure to coolant pressure.

http://www.steigerperformance.com/products/pics/sp40001.jpg

[Mad Dog 20/20]

Are you BOILING the coolant, or are you seeing evidence of the coolant having sprayed from the cap?

Boiling generally means you have a breach in the system somewhere preventing the coolant from reaching normal operating pressure and thus it has too low a boiling point.

If the coolant is being belched/sprayed from the cap (but not boiling), then the coolant pressures are too high (likely HG) or you have a defective cap.

[charger758]

It is belching out of the cap, and when I open the bleeder the water is definitely boiling.

[Mad Dog 20/20]

It is belching out of the cap, and when I open the bleeder the water is definitely boiling.



I'd tighten all the hose clamps, including the ones at the firewall, coolant pipe and and TB and try a new res cap. Is the coolant resevoir old or swollen? If so, I'd replace that too and go w/ a brass bleed screw.

[agu845]

Are you BOILING the coolant, or are you seeing evidence of the coolant having sprayed from the cap?

Boiling generally means you have a breach in the system somewhere preventing the coolant from reaching normal operating pressure and thus it has too low a boiling point.


If you had a breach wouldnt you get coolant leakage directly from the breach point?

[Mad Dog 20/20]

If you had a breach wouldnt you get coolant leakage directly from the breach point?
Yes.
Sometimes people dont notice a small leak because they assume the coolant around the engine bay or on the ground is coming from the cap or from them repeatedly filling/bleeding the system. Checking hoses and replacing the cap/res are cheap/easy ways to rule-out a leak of some sort, and is likely replacing/checking stuff that needs to be replaced/checked anyway.

Boiling coolant is usually not from over-pressurization, though. And the lack of overnight pressurization of the system points to something else. Higher system pressure = higher boiling point. Depending on how much coolant vs. water he runs, it could easily go to 280 degrees without boiling @ 2 bar. If he is seeing 280+ coolant temps, then his head is likely shaped like a Pringles chip and he would be having serious definitive HG symptoms.

[agu845]

thanks for the explanation.

My system IS definitely leaking combustion gas into the coolant, (upper hose rigid, gas escapes 2-3 days after sitting idle and when pressurized I get a "add coolant" warning on obd that goes away after i open cap and relieve pressure). I had sort of been hoping that there might be some other explanation for this, but have concluded my HG is failing. For the driving I do (i.e., not tracking/planning on tracking the vert), temps are still right on, doesn't go above 210, so for now, I'm driving and waiting for temps to creep up on, then do what has to be done.

[Sniz]

thanks for the explanation.

My system IS definitely leaking combustion gas into the coolant, (upper hose rigid, gas escapes 2-3 days after sitting idle and when pressurized I get a "add coolant" warning on obd that goes away after i open cap and relieve pressure). I had sort of been hoping that there might be some other explanation for this, but have concluded my HG is failing. For the driving I do (i.e., not tracking/planning on tracking the vert), temps are still right on, doesn't go above 210, so for now, I'm driving and waiting for temps to creep up on, then do what has to be done.

honestly, tear into it now. The temps likely wont creep up, rather shoot up like a rocket when you are in the worst possible location. Thats what happened to me.
:eyecrazy

[stanksbeamen]

thanks for the explanation.

My system IS definitely leaking combustion gas into the coolant, (upper hose rigid, gas escapes 2-3 days after sitting idle and when pressurized I get a "add coolant" warning on obd that goes away after i open cap and relieve pressure). I had sort of been hoping that there might be some other explanation for this, but have concluded my HG is failing. For the driving I do (i.e., not tracking/planning on tracking the vert), temps are still right on, doesn't go above 210, so for now, I'm driving and waiting for temps to creep up on, then do what has to be done.

I drove my car for a few months like this. I had the same problem, pressurizing of the coolant/hard hose. I was driving to work one morning and glanced at my temp gauge going past the middle but not yet to the 3/4 mark. I pulled off and shut it down, luckily I wasnt far from home but I can only imagine if I was...


honestly, tear into it now. The temps likely wont creep up, rather shoot up like a rocket when you are in the worst possible location. Thats what happened to me.
:eyecrazy

+1

[charger758]

+1 on the temps shooting up really fast when they go above the norm.

Ok guys here's my findings. I hooked the pressure sensor up to the upper radiator hose. I let the car fully warm up (fan cycled 3 or 4 times), pressures were around 6psi. I started driving stayed out of boost, the pressures were around 4-6psi. Then I hit the freeway and began flogging, the pressure slowly climbed to around 17psi after about 5 hard pulls, temperature looked good.

Pulled off the freeway and the pressure slowly came down to about 15psi. I did a half mile to a mile of 2nd gear stomps then brakes over and over, the pressure eventually hit 22psi and the temperature started shooting up.

Not sure what normal pressures for the upper hose are. I was hoping to see something more definite, like 50psi spikes or something. I'm thinking about just swapping to head studs one at a time and not replace the head gasket and repeat this exercise. Then if that doesn't work, go for the gasket.

I'll try to remember to check the gauge in the morning. When I shut the car off I think I was around 16psi.

Also would you guys suspect the upper rad hose would have the same pressure as the tank? If so, that is probably why I only saw the 22psi since I think the stock cap pressure is around there (correct me if I'm wrong).

[BadBoostedBmwM3]

IIRC, the stock cap is like ~26 psi. Something real close to 22psi.

[Neil]

thanks for the explanation.

My system IS definitely leaking combustion gas into the coolant, (upper hose rigid, gas escapes 2-3 days after sitting idle and when pressurized I get a "add coolant" warning on obd that goes away after i open cap and relieve pressure). I had sort of been hoping that there might be some other explanation for this, but have concluded my HG is failing. For the driving I do (i.e., not tracking/planning on tracking the vert), temps are still right on, doesn't go above 210, so for now, I'm driving and waiting for temps to creep up on, then do what has to be done.

If you're still running stock head studs, you might consider replacing them -- one-by-one -- with ARP 2000 studs. Given that you don't track the car, this may be sufficient to address your problem.

In any event, the ARP studs can be re-used if you decide that you need to replace the head gasket.

Neil

[charger758]

Well, 24 hours later the upper rad hose has 2psi in it. I ordered headstuds today, we'll see how it pans out.

[stanksbeamen]

Well, 24 hours later the upper rad hose has 2psi in it. I ordered headstuds today, we'll see how it pans out.

By feeling the hose was it hard? Soft? Hopefully ARP 2000's will do the trick for you

[Bimmer Man]

If you're still running stock head studs, you might consider replacing them -- one-by-one -- with ARP 2000 studs. Given that you don't track the car, this may be sufficient to address your problem.

In any event, the ARP studs can be re-used if you decide that you need to replace the head gasket.

Neil

What is the procedure to do this?

I know when installing ARP 2000's on a new gasket it is torque to 32 ft/lbs then two 90 degrees which usually ends up being over 130ft/lbs.

When installing one by one do you just torque to 130?

[GT110]

What is the procedure to do this?

I know when installing ARP 2000's on a new gasket it is torque to 32 ft/lbs then two 90 degrees which usually ends up being over 130ft/lbs.

When installing one by one do you just torque to 130?

Follow the instructions which come with your box of ARP2000's.

My box (from FEB 2010) came with 105Lbs (or was it 110) in 3 stages, not the 32-90-90.

[charger758]

I am planning on replacing the studs one at a time and only torque to the first sequence. Then when all of the headstuds are in torqued to that first sequence I'll repeat that first sequence on all studs then complete the last 2 sequences on all studs.

[bmw_e30]

I had the same issues as you OP.

I basically only track my E36 M3 AA C38 Stage II.

Started slowly overheating about a year ago towards the end of my sessions at the track. Then it got worse.

I just did a OEM HG + ARP 2000 + Groma oil cooler kit + Spal 2360 cfm race fan wired for 2 way operation + 80 degree fan switch + distilled water/ww + Mishimoto radiator + 75 degree tstat.

My overheating issues are fixed hopefully lol. :evil2