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Help! Overheating E30


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We've had some cooling issues with our new-to-us E30. The car has an M50 engine swap, and in the two test days we've done seems to come up to about 210F after 5-10 laps. We're running deio with redline water wetter (1 bottle).

 

We're working to get this resolved asap as we are racing at Mosport this weekend for our inaugural race! We have flushed the system (multiple times now) by draining from the lower rad hose, and the engine at the thermostat. The flush produces clear water, so we aren't worried about buildup or a dirty system. Upon filling, our main concern is that it only seems to want to take about 4.5L of water. My reading tells me this should be much more (11?). Our rad does not have a bleed screw, it has a nipple that is plumbed back to the expansion tank. We burb the hoses and try to get air out, and run the engine to pump the water through the system but the level has not gone down (I was expecting to have to keep topping it up as the water filled the system and bled out). I imagine some of the system is still filled from the flush stage, so I wouldn't expect it to be bone dry and require the entire capacity in filling, but was expecting more than we added. Finally, we've verified the thermostat works (it opens at 190F, we have a lower temp tstat waiting to go in). My next step will be to check the water pump, I've heard the stock ones were plastic and often have impellers break.

 

Anything we're doing wrong here? Anyone else running this engine have any tips? Couple questions:

 

For draining:

 

What should the capacity of the system be?

How much will remain in the system after draining it?

Is there a drain on the engine block itself to fully purge?

 

For bleeding:

 

What method do racers use to bleed their cooling systems?

Any other tips for keeping temps down? We've been told 190-200 operating.

 

Thanks everyone!

-Jonathan

Edited by Vitamin-E Racing
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Nice work guys!  Hahaha, cutting it close though for Mosport!  FWIW we just finished up our prep last night on a brand new car, (so we aren't much better!).

 

A few points, that may or may not be helpful as I don't know anything about E30s.  We had major overheating issues with our first car (mazda 626) and had our inaugural race as Mosport, so feel very similar!

 - does the temp continue to climb past 210 or do you just bring it off track at that point?

 - Have you cut the front end up and are allowing air to by-pass the rad - it will take the easiest route just like water flowing in a river.  Block those areas and/or create ducting to direct air through the rad.

 - We found that hood louvers really helped.

 - Head gasket?  We aren't sure if the head gasket was the cause or the symptom of our issues, but it certainly didn't help in the end.  Probably worth a look at it.

 

Also, considering the forecast... Id say you are going to want your car cooling to its maximum capacity this weekend!  Going to be a warm one!

Edited by thewheelerZ
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I ran a m50 for two seasons in an e30. When I had problems with overheating it was because there was air in the system or there was a leak. Have you done a coolant pressure test to make sure nothing is leaking in your system?

 

I ended up taking the thermostat out in my m20 because I overheated at a race and caused the water pump to fail (stuck tstat). 

 

It's interesting that when you drain and refill you're only putting in 4.5L. Usually when you drain and fill you should be getting 10 to 11L.

 

I would check the water pump if none of the above fixes it. 

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pressure test your system!    we had similar and upon pressure testing we found weak areas.

 

running water wetter and distilled water we are able to stay sub 200 with an ebay radiator.  I also recommend you have factory shrouding in front it it to force air through.

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Unfortunately for you the "cooling" topic for the champcar tech series is pretty far in the future. But I can give a few quick pointers

  • Most champcar overheating I have seen is airflow or fluid loss related. Most OEM rads will cool more than enough for us, because they are designed for low airflow (going slow).
  • Make sure your ducting is solid, intact and you have all the parts. In the neon the loss of the lower air dam\ rad support extension is worth 30+ deg water temp. Most cars use the static pressure (giant flat surface at rad support vs a duct) method of cooling air, so you need to seal up everything but the rad. Pulling the ac condenser, headlights, etc makes gaps.
  • Buy a pressure tester with adapter for you car. It is worth its weight in gold. Hook it up and pump the thing way up. Using soapy water in a spray bottle look for leaks (they will bubble) when you spray all the water paths. 
  • With pressure tester hooked up fire up engine and rev to 3000 rpm with as much load as you can put on it (i brake against engine with wheels off). The pressure will rise with temp, but if you can raise the pressure a few psi in a matter of seconds, you have a blown head gasket charging the water system. Did this in a car once, as soon as we floored it on track it would push water (combustion pressure was above rad cap blow off). 
  • If you overheat it be patient and wait for it to cool down. You need to verify how much water it takes to determine if there is a leak. You will also warp the head when you slam cold water down its thermonuclear throat. 
  • When in doubt, you probably have a hole in the rad. New rads are thin for most cars and get pinholes looking at stones. I search for OEM rads and pay more for it even if it is more than some aftermarket copies. Use screen to protect it, and thank our "durability cost points" advocates when you can't run an oem or cheaper aftermarket "drop in" aluminum rad with thicker tubes for protection (and most likely less cooling capacity) :) 
Edited by Black Magic
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I can tell you that my old Schumacher Taxi teammates also run an M50 swapped e30 and they routinely run, on track, at 240 degrees.  I radio'd in concerned at Charlotte and they told me "yeah, that's normal".  Just a point of reference for you.  

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58 minutes ago, Jer said:

I can tell you that my old Schumacher Taxi teammates also run an M50 swapped e30 and they routinely run, on track, at 240 degrees.  I radio'd in concerned at Charlotte and they told me "yeah, that's normal".  Just a point of reference for you.  

 

Holy crap that's hot! 

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5 hours ago, Vitamin-E Racing said:

We've had some cooling issues with our new-to-us E30. The car has an M50 engine swap, and in the two test days we've done seems to come up to about 210F after 5-10 laps. We're running deio with redline water wetter (1 bottle).

 

We're working to get this resolved asap as we are racing at Mosport this weekend for our inaugural race! We have flushed the system (multiple times now) by draining from the lower rad hose, and the engine at the thermostat. The flush produces clear water, so we aren't worried about buildup or a dirty system. Upon filling, our main concern is that it only seems to want to take about 4.5L of water. My reading tells me this should be much more (11?). Our rad does not have a bleed screw, it has a nipple that is plumbed back to the expansion tank. We burb the hoses and try to get air out, and run the engine to pump the water through the system but the level has not gone down (I was expecting to have to keep topping it up as the water filled the system and bled out). I imagine some of the system is still filled from the flush stage, so I wouldn't expect it to be bone dry and require the entire capacity in filling, but was expecting more than we added. Finally, we've verified the thermostat works (it opens at 190F, we have a lower temp tstat waiting to go in). My next step will be to check the water pump, I've heard the stock ones were plastic and often have impellers break.

 

Anything we're doing wrong here? Anyone else running this engine have any tips? Couple questions:

 

For draining:

 

What should the capacity of the system be?

How much will remain in the system after draining it?

Is there a drain on the engine block itself to fully purge?

 

For bleeding:

 

What method do racers use to bleed their cooling systems?

Any other tips for keeping temps down? We've been told 190-200 operating.

 

Thanks everyone!

-Jonathan

As others have noted, 210 doesn't seem to be out of the ordinary.  Did you have other "symptoms" when you were track testing it (i.e. did it start steaming or blowing coolant out of the overflow?).

 

In every car I have ever owned, you could easily see if the water pump was failed.  I'd start the car from cold with the rad cap off.  It would be easy to see the thermostat open and the flow of the water pump by just looking in the opening (suddenly the water would go from static to moving left to right or right to left). 

 

As far as bleeding air, we would jack the car up really high in the front, with one side higher than the other, such that the radiator cap was the highest point in the system.  Then we would run the car, wait for the stat to open, and see if it "puked" out coolant.  When the puking was done, we did repeated gentle revving of the motor.   That moved the air through the system and over to the opening.  A sure sign that you have air in there is that coolant will surge out without you even revving the car.  That is an air bubble getting to a hot spot in the head, expanding rapidly, and pushing coolant out as a result.  Don't start the revving until the "puking" is done.  Don't worry that the coolant gets a little low during this process, but make sure it doesn't get below 1/2 height in the radiator (just add while it continues to run if you need to).  Once you have gone through the initial puking and then the cycle of revving, it should stabilize and only do small surges in level.  That is your indication that you probably have the air out.  At that point, top it off while it is still running and then put the cap on.  Fill the overflow to the "hot" line on the tank (since the engine is fully hot) and see how much gets pulled back in after you let it cool.  With some luck , it will go down to the "cold" line.  If it goes lower, bring it back up to "cold" again.  If it keeps wanting more, you probably have a head problem and are sending coolant out the exhaust (which will definitely cause the coolant to get too hot).

 

NOTE:  Based on the refill quantities you mention above, there is a good chance that you could have made things worse (i.e. trapped air in the system) with your flushing and filling.  Make sure you do something (whether it is the above or something else) to ensure that you have the system full of fluid and not air, or you will see 210 after two laps.

 

Good luck!  (if your car doesn't have a radiator cap, then this won't help you much but maybe it will help someone else)

Edited by Racer28173
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Our really scientific and accurate temp gauge (Bluetooth Meat Thermometer taped to the upper hose) shows on track temps in the 190's to 200.  240, if correct and in the head seems really, really hot.  On my personal car I start backing down at 220 in the head.  I know the M50's are a pita to bleed, and I've taken to drilling a hole in the thermostat to assist in bleeding, as well as parking on a hill and burping the system.  Then let it cool overnight and you should have to fill some more in the morning.    

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19 minutes ago, Jab31169 said:

Our really scientific and accurate temp gauge (Bluetooth Meat Thermometer taped to the upper hose) shows on track temps in the 190's to 200.  240, if correct and in the head seems really, really hot.  On my personal car I start backing down at 220 in the head.  I know the M50's are a pita to bleed, and I've taken to drilling a hole in the thermostat to assist in bleeding, as well as parking on a hill and burping the system.  Then let it cool overnight and you should have to fill some more in the morning.    

I've drilled a hole in the tstat of every M20 I've raced.  I don't see why it wouldn't help in an M50.

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Advance rents a tool that you can use to check for leaks:

image.png.62ec08bafe3fc9c27817e83bcb293eb3.png

 

Proper bleeding procedure:

image.thumb.png.c8cfa2342a0560f5944b7d166d8d5907.png

 

Vent hole goes up like Ed says

image.thumb.png.5fedbfb6b16cdeeb2dd8a26ad30ced2d.png

 

T-stat is supposed to open at 80c on non-vanos and 92c on vanos motor

image.png.f3ce6e26c3a2b42986f4495093b5e877.png

image.png.83b3c50e8e36165992b374c1711c694b.png

 

Cooling volume , but will be less if you deleted heater

image.png.62726516457b870a631a255fded3a148.png

 

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Hey everyone!

Sorry for the late reply - I've been reading all the posts and am floored by all the responses and support, and was busy getting the car ready for last weekend's race! You've all helped us resolve the issue!

 

Quick summary as it may help others. It seems the problem was likely a combination of things:

1) We were not "completely" flushing the system as we were not draining from below the block (ie, half the block still had old water in it). This explains the lower quantity of liquid it was taking on the refill.
2) To be safe, we replaced the water pump. Turns out the old one was already a metal impeller type, but we replaced it with a new metal impeller type anyway. Now we have a spare!
3) We installed a lower temp thermostat (71C).

4) We did a complete flush (taking out the water pump drains from a pretty low place in the engine!) and properly bled the system. This is likely an area we were lacking previously. What I was finding (we have no cap on our rad, and no bleed screw, just an overflow nipple plumbed to the expansion tank) is that when burping the system, rather than air being released, it was pushing fluid through the overflow back into the expansion tank (path of least resistance). So what I did was plug the overflow with my finger and burp the system, which forced air out rather than liquid. This helped huge, as evident by eventually having no bubbles when squeezing hoses.
5) Finally, and what we think may have made the biggest difference, is we noticed that the lower rad hose was kinked where it bent upwards towards the engine. When I say kinked, I mean the hose was too long and where the regular bend is, the hose was bent double - probably a 50% blockage. We cut the hose to proper length and the kink was no longer evident. We are adamant that this greatly improved the system operation.

 

All in all, we got on track and the car ran consistently 180-190 the entire weekend! We couldn't have been more happy, as this was definitely the largest worry we had going into our first ever race with the car at Mosport!

 

Thanks again for all the replies - you've all been a fantastic help!


Next step is going to be some hood vents, can't hurt, and a noticeable airflow building and pushing up under the hood while on the back straight! 
 

-Jonathan & Alex
ecstasE30 Racing

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