M62TU overheating

[ibumpers]

A few weeks ago when I did whole coolant system replacing I had the same problem I followed the link to the t but it took me 6 times to get all air out of system and no more over heating
1998 740i

[kouks]

What is the safest way of testing it? I saw somewhere a newspaper but that sounds dangerous if the fan is operating.

Yes, the newspaper trick works fine, or a magazine. Slowly come at it from the rear (so to speak) and press the rolled up newspaper to the back of the fan. If the fan stops turning with only a bit of pressure, you need a new fan clutch. If it fights back and continues to turn, its OK.

If everything was working fine before the water pump issue, it just needs a good bleeding. Follow the directions Timm posted. Having the nose up on an incline helps a lot. One trick I use is to fill the radiator, leave the cap open, and start the car, as the level drops as the coolant is being drawn in, I keep adding to keep the level sensor up to the top of the fill. As I see it getting hot, I screw on the coolant cap, and open the bleed hole a bit until no air bubbles out. Then tighten the bleed and shut it down, let it cool several hours, check the level and add any coolant as needed. Let it stand overnight until completely cold and check level again, add as needed. This works for me, and I carry a bottle of coolant with me the first week of driving and check every morning when all cold, add coolant as needed. Once the coolant level stabilizes, its good to go. My e38 is from hell, I've had this thing apart so many times that I've gotten good at the coolant thing. Works well every time.

[Frenchi]

I bleed it with timms instructions, ran a head gasket test came back negative for blown gasket, tested the clutch fan she fights back against the newspaper... could there be some kind of blockage? If I drive past 100mph it cools back down which leaves me confused.

[georgebest]

What if you connect an ODBII scanner and monitor temperature? I'm curious what is actual temperature cause gauge is quite unreliable.

[purplecty]

I changed my Thermostat, with an OEM one, but its still overheating. Bled it 3 times to the point where im getting a steady stream of coolant running out of the bleeder screw, coolant level when the car is 8h cold is showing where its supposed to be. I dont understand how it could still be overheating.

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I cant tell because my pixels are shot. I dont think we have something similar because im running an e39 m5 cluster, unless you are too :P

Is the m5 cluster programmed properly to read the coolant temp? If not, maybe it appears it's overheating but its really not? I think a non properly programmed m5 cluster causes the temperature needle to go beyond the half way mark...

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[georgebest]

I have just had this today; on exact same temperature (104C) the gauge was dead center and a few minutes later went almost 3/4. Almost like it's using a different sensor or something. I was monitoring temperature on ODB.
It could be just my, but the gauge is entirely useless.

[Frenchi]

Is the m5 cluster programmed properly to read the coolant temp? If not, maybe it appears it's overheating but its really not? I think a non properly programmed m5 cluster causes the temperature needle to go beyond the half way mark...

but why why would it start acting up now? It's always worked perfectly fine for over a year

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but why why would it start acting up now? It's always worked perfectly fine for over a year

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I'll stop at advance autoparts tomorrow and find out what's it's actually reading it you do feel the performance loss unless it's a placebo

[purplecty]

but why why would it start acting up now? It's always worked perfectly fine for over a year

So that means no the cluster was not programmed correctly? Do you know how to unlock your cluster?

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[Timm]

Here you go:

http://www.meeknet.co.uk/E38/OBC_Unlock.htm

You need Test No 7

[georgebest]

So that means no the cluster was not programmed correctly? Do you know how to unlock your cluster?

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He said he had dead pixels so even if unlocked wouldnt be able to read it. He needs a cheap ODB scanner to monitor the temperature.

[740iSport303]

He said he had dead pixels so even if unlocked wouldnt be able to read it. He needs a cheap ODB scanner to monitor the temperature.

Then get an ELF bluetooth and Torque Pro for his smartphone. Can see most items with that little setup.

[Frenchi]

I replaced clutch fan with a new OEM (at this point anything is worth trying), no progress this is crazy I put the old cluster back on and gave me the same results as the m5 cluster.

[MrChrysler]

If you really want to know that your system is bled from the air, follow this:

1. Make sure that the car is standing on a straight surface, or that the front of the car is higher than the back of the car.
2. Engine must be cold
3. Take off the radiator cap, make sure that its just slightly overfilled.
4. Undo the top radiator hose on the radiator side (highest point), not at the water pump side. Start sliding it off slowly - The hose should be full of coolant. If the coolant starts leaking out than you know that its bled successfully (I mean more than few drops, as i said it should be full of water).

If the system was not bled successfully before, you should see that the water is disappearing in the expansion tank.
If the hose is empty, you can add coolant directly into the hose (easiest way for me) - when you fill up the hose put it back on. Check coolant level in the expansion tank.
If you do that your system is 100% air free.

It should take less than 10 minutes.

Report back.

[MarkZ28]

Anything get in the way of tbe radiator, like paper or a rag that fell down in front of the radiator? Never know. Sounds like a partially blocked radiator since you have rrplaced everything else. Have you tried checking the temp with an outside source such as a temp gun or a thermometer? That would eliminate any computer confusion in the system. Check the temp where the sensors are and the radiator, anywhere theres coolant. Water pump would be good to check also if you can get a direct shot at it. If yours has the electronic thermostat, make sure its plugged in.

[Frenchi]

I'll give it another try, but could it be the Heater core pump that died too? Seems everything is failing at once.

According to INPA
coolant temp is hovering between 105-106.5c
(if I get the RPM up on the highway at I can lower the the coolant temp to about 95-99 ) if not it creeps back up
lower radiator hose is at 32-42c
engine temp 105c
Tranny temp 89-93c

[georgebest]

I'll give it another try, but could it be the Heater core pump that died too? Seems everything is failing at once.

According to INPA
coolant temp is hovering between 105-106.5c
(if I get the RPM up on the highway at I can lower the the coolant temp to about 95-99 ) if not it creeps back up
lower radiator hose is at 32-42c
engine temp 105c
Tranny temp 89-93c

So you have perfect temp everywhere?? Lol

[Timm]

Yes, that all sounds hunky-dory to me too.......

[purplecty]

Mine runs at and avg of 108 to 109c and sometimes 110c. When the aux fan kicks on for 20 or 30 seconds a few times it goes back down to 106 then to 108 even when driving at highway speeds...

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[georgebest]

It seems he has the exact same problem what I have; unreliable gauge. Lesson is not to relay on the gauge alone. Mine can show almost 3/4 when temp is 108C, I couldnt figure yet why and have more pressing issues...like starting up the car

[Frenchi]

Here comes a million dollar question, how to modify the values to reset the gauge? I tested the car for a week the absolute highest value I saw was 108c, therefor it’s safe to say that I’m not going to blow a head?

[georgebest]

Here comes a million dollar question, how to modify the values to reset the gauge? I tested the car for a week the absolute highest value I saw was 108c, therefor it’s safe to say that I’m not going to blow a head?

I’m trying soon by replacing the thermostat in the water pump, just waiting for the part to arrive. Have no other idea, my guess it’s getting the readying from there but not sure.

[oldroller]

Hundred dollar answer to million dollar question: 88c thermostat from ECS Tuning, bolt on, temps 93c-96c.
Lower pressure, lower temps, lower worries.

[purplecty]

Hundred dollar answer to million dollar question: 88c thermostat from ECS Tuning, bolt on, temps 93c-96c.
Lower pressure, lower temps, lower worries.

I got mine from amazon UK but haven't installed it yet...

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[georgebest]

$116.78 at ECS

Do you get check engine light when using it?

[Jackwagon]

Did you try flushing the radiator and condenser? Use a garden hose turned on full blast and direct the water flow through the radiator and condenser
from the rear (engine side) of the radiator towards the grill.
Maybe you're overthinking it.