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Motor is an S52. Overheated one day and tried a bunch of things to fix it but it would not stop overheating after 20minute drives. Coolant and block test were inconclusive, and the coolant still steamed. So I tore it apart. Replaced the HG with an elring kit. Head was corroded bad so I purchased a refurb decked head. Cleaned the block and replaced the HG and cooling elements, and recently before the HG had put an S54 radiation and new clutch fan in it. Has metal impeller pump and new Tstat as well.
Anyways, when I drive the car 20 minutes hard I can get the needle past the 12 o clock position. When I do this and crack the bleeder screw, it is all steam that comes out. If it doesnt overheat and I crack the bleeder it is all coolant. I am sure the system is bleed and I rebleed it Every time it overheats.
Looking for any help or suggestions here with sound reasoning or personal experience. What would cause coolant to boil besides the HG not sealing? I know there is a good chance the HG could be bad but id like to think of the other possibilities as well. The HG tests were inconclusive before so I am going to skip them.
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Are you using new OE torque-to-yield head bolts and washers, installation per Bentley?
Or ARP studs, washers, and nuts?
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I went with OE bolts, new. Installed to specOriginally Posted by bluptgm3
Last edited by be4life182; 05-21-2019 at 02:10 PM.
Balogne Cajones
Was the block clean, no digs or gouges? Was the head from a "guy" and not a shop? Do you bleed the system with the heat on full in the car? Did you do the torque sequence and not just the first step to the 22lbs or whatever?
If all was a yes, you probably got a head that no one checked for cracks, because people are dumb, decked it thinking it was just warped, and sold it to you. After a heads been decked the cracks hide in the new surface finish. Its happened to several friends of mine.
If its still eating several jugs of coolant, the option is to pull it and do it again. Luckily, youl only need a new gasket and the time to do it the second go around as the studs probably didnt expand out of spec. And the coolant ofcoarse. A couple heat cycles is alls a crack needs to show back up after a machining.
Nobody would recertify these machines after somebody screwed with them without any visibility into what they did.
HONK! HONK! Clown car coming through!
-Oakdizzle
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I believe you need new torque-to-yield bolts.
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Where did you learn to open the bleeder screw on a hot engine. You know when the engine is hot it's under pressure and that is what keeps it from boiling, when you remove that screw it's no longer under pressure and will boil out. Never open the cooling system when its hot, plain and simple.
How far over the 12 o'clock mark does it go?? If its only like 1/16" or 1/8" then thats normal unless you have a 180 thermostat and the lower fan speed temp switch 80/88. If you have the normal fan temp switch installed you can try wrapping the switch in an insulator (I used foam) and that will allow the fan to come on at the appropriate temp (poor design on these switches). I have the 80/88 fan temp switch and it will only come on at those set temps if it's wrapped in foam.
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So I got the head from peter at autoheadperformance.com. Bleed it correctly, torqued in sequence, to spec. I believe he checks for cracked but I guess it could be cracked, I would never know. Although it has the same symptoms as before the HG.
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I didn’t learn it anywhere except when I believed exhaust was getting into the cooling system, so I checked to see. Its a lot of steam so I figured it wasnt flash steam from pressure release...its as if its full of steam prior to opening. I have the OE switch and thermostat temperatures. IT will usually stay between 1/2 and 3/4 on the gauge but it would keep going if I let it..which I don’t.
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Some radiator data...if you have any data from personal teats using an IR thermometer please chime in.
After a 20 minute commute, and then a 5 minute romp, the needle is at a little less that 12 o clock. Normal position. Lower rad house near outlet reads ~212, upper rad near inlet reads ~234. These numbers are too hot but should the difference be greater? Is my rad working properly?
I then insulated the aux fan temp guage. Drove around to redline for 20 minutes, did not move past less than half. Upper read ~201 and lower ~177. After idling 5 minutes after the hard drive upper reads ~204 and lower ~180. Fan is running a lot more but not constant. Did I mask it or do I owe Eric93 a beer?
Last edited by be4life182; 05-21-2019 at 09:56 PM.
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Sooo, there's nothing wrong with your car. You can permanently put insulation on the fan temp switch, mine is sandwiched in styro foam and duct tape. I would recommend putting the 80/88 fan temp switch and the 80C thermostat. Look up the FDM thread (fan delete mod) to get the part numbers.
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Why did you state earlier that the temp gauge could hit the 3/4 mark, and now you say it doesn't? What's changed?
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Your new thermostat my not be opening enough. I would do the 80/88 switch and the 80 thermostat.
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well, I am still not convinced that nothing is wrong for certain. I still think it is not cooling enough on its own (maybe the WP...maybe a clogged radiator), and the aux fan turning on more frequent and earlier is simply masking the problem. Now it could be the fix but I am not liking the small temperature difference between the radiator inlet and outlet.
The only thing that changed from it overheating to the 3/4 mark is the insulation and the help from the aux fan.
Not sure on thermostat but it is the second new one in two months, both yielded same results before I insulated the temp sensor.
Can anyone provide data on what % the radiator temps should differ?
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Your hose temps seem normal for your thermostat. Post a link to the exact wp you have.
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Are you under driving (power pulleys) the water pump?
And what water pump are you running?
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Balogne Cajones
You think the auxilary fan turning on and cooling the engine like its supposed to is "masking the problem". Lols
Nobody would recertify these machines after somebody screwed with them without any visibility into what they did.
HONK! HONK! Clown car coming through!
-Oakdizzle
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No. However a good cooling system should not kick the aux fan on as often as mine now kicks on. After a week of driving and monitoring temps I can confidently say it is still getting too hot for normal driving, although the aux fan is keeping it from overheating for the most part. I did see the needle go up a tiny bit the other day.
It would be nice to hear someone elses IR thermometer readings on the hoses. Looks like I am just going to do a new WP and flush the radiator again and hope its one of those. Not sure the current brand, maybe graf. Metal impeller that looks zinc plated.
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Are you using a cast impeller WP?
I would go to an OE, OE type (composite Selari), or a stamped/welded (Hepu) impeller pump.
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Get the 80c thermostat. I doubt your water pump is bad, but I would get the Resin pump by Beck/Arnely rockauto has.
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You shouldn’t be relying on the factory temperature guage while you’re driving either add a real guage or get a Bluetooth Or WiFi obd reader and use a phone App to keep an eye on your temperatures .
Additionally check your electric Aux fan to make sure it’s pushing air into the engine.
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Does this car have a fan clutch or just the aux fan? If just the aux fan, expect it to run more than it did when there was a fan clutch. And use an 80 thermostat and 80/88 switch. The thermostat starts to open at its rated temp. It can take 10 to 20 degrees to fully open. The aux fan senses from the cold side of the radiator, after coolant has passed through it, so there will be a temp differential. It is turning on only if the temp is still high after the radiator has tried to do its work without fan assistance. If you run a lower thermostat and fan switch, they will work better together.
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I will replace the switch and water pump (composite) soon. I have a brand new aux fan as well, I forgot to mention that. Before I did the HG I tried that as the OEM one didn't fair well to the newspaper test.
I would still like to figure out why it is getting too hot though. Maybe I will do a radiator backflush again before the WP to see if there is any improvement. Everything else is new so it is either the WP, blocked radiator, or exhaust is still getting into the coolant from a bad HG. Hopefully it is not the headgasket as I will not be doing that job again, although the system seems to be staying bleed now.
Can't think of what else it would be but I will keep testing the temps and try and figure it out because as everyone knows throwing money at an E36 until something sticks can be quite frustrating.
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There are a limited number of explanations. Not bled, bad thermostat, bad water pump, bad fan clutch, bad radiator, bad fan switch or aux fan, cracked or warped head or blown gasket. You seem to have done enough to rule most of them out.
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Is it possible to install the theromstat incorrectly? Pellet end goes towards the engine lol.
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I agree, I did what I could to rule most things out but something is still making it run hot, which it never did when I first got the car. Makes you bang your head against the wall for sure.
It is installed correctly, including arrow pointing up lol. Don't think it would seal too well in backwards lol
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