[tpao6spd]

The M62TU engine was engineered to run at high temperature, unlike the S62 engines. It does put a lot more stress on cooling components. If you want to reduce cooling system failure, maybe going to waterless coolant will help reduce the stress, but not the operating temperature.

 

[4thBMW]

That's a thought...waterless.

I think back to blowing hoses, etc in the 1988 E32 picking up someone at LAX and not getting off the 101 in time to save my head in Ventura...you can just cook an car on the 101 south into LA.
I did do something productive last weekend while wrapping my tranny electric cable wires and slipping some new plastic flex pipe over them...I pulled a handful of oak leaves out of my radiator and behind those flap openings.

 

[ninetyseven]

88C thermostat, and to avoid any thermostat error codes (not CEL's) cut the thermosat wires and install a 12 ohm 100watt resistor. I have run this combo for over 5 years , no issues and no errors or codes. Car runs at 90C around town. hot factory thermostat is the reason cooling system fails, gaskets leak and timing guides go out.
https://www.ecstuning.com/b-vemo-parts/thermostat-with-gasket-88c/11512248542~vmo/

 

[Santaclaus4]

hot factory thermostat is the reason cooling system fails, gaskets leak and timing guides go out.

No disrespect intended but I don't believe that's quite true. Higher relative coolant temperature does relate to higher coolant pressure. The radiator and overflow tank have a couple week points that weren't engineered properly to withstand the "pressure cycles" as long as we expect them to last. Basically the radiator or overflow tank fail sooner and "typically" more catastrophically than we expect from most cars and trucks. The timing chain guides are more anecdotal. I really wish we had more exacting data on what causes them to fail. Mine are well into the typical fail age (150,000-200,000) miles. I'm just waiting...

 

[4thBMW]

Hi Santa

I changed out my M62TU chain tensioner cartridge not long ago for the second time now in 150,000 mi. so, I'm on my 3rd. I saw no real difference in the springs inside the tensioners. However, if the engine oil has particualte that wear the tube surfaces, maybe that hydraulics of that tensioner degrade, leak sitting for a long time, I do not know. I change my oil on average 5-7000 mi. and also sometimes change the oil filter in between. i'm not too worried about the occasional brief startup rattle these engines make.
Back to the 88deg C thermostat, My exhaust valves ( and intake) stay clean without any special treatment other that COSTO tier1 93 octane and 1 can of Chevron fuel cleaner right before oil changes. I've decided to keep running in the 'mapped' coolant temp range. I hop the new stock t-stat will get the temp down under load. most of my driving is around town feathering throttle.

 

[4thBMW]

Bar's Leak brand 10 Minute Radiator Flush

I may have mentioned I was going to flush with the above mentioned, non-acidic, coolant flush. Got some sent to me by Walmart. Have not used it. Spoke with Bar's Leak tech. customer support. He would not tell me the active ingredient(s) or anything other than the product had been discontinued and wanted to know where I bought it.....before putting me on hold (end of call). I'm returning the stuff to Walmart. just from what I gleaned from some product revies, 10 Minute Flush is probably a benign organic, biodegradable sufficant (like Myer's dish washing soap) that I can buy from COSTO for $10 / gal. I decided not to have a bubble party and flush with water. Hell...I've never seen anything but clear coolant in my system and replace those parts more than I care to remember. LOL.

 

[Burning2nd]

never use any of that stuff... a flush is drain and fill.. and repeat

 

[4thBMW]

I hear ya. Funny, that thermostat i pulled,

I could not get a good ohm / resistance reading as mounted on pump. just pegged 1.0 like a short. Now, on the bench, reads 13.3 -12.7 ohms. Seems and acted normal. New, out of box replacement was 13.7 Ohms...now installed.
humm, old stat had some pitting, corrosion inside. Installed w/ new pump, rad. 11/2016. Sprayed some Deoxit D5 all over it and on the shelf with it.

 

[JimLev]

4th,

I read an interesting suggestion from JimLev, about heating the spring on the T-Stat.
That drops the temp needed to open the 'Stat.
He has reported a tempt reading avg 100 to 103 in the summer, with AC.

https://www.bimmerforums.com/forum/showthread.php?2106675-Modifying-M62tu-thermostat

Something any WalMart shopper would be proud of!
Sorry Jim, couldn't help it...
Of course, I can't wait to open my T-Stat, and get to heatin'.

Cletus

That was just a test to see if it was a viable option. In the end I decided to put the original t-stat back in and then built an adjustable PWM controller that I connected to the t-stat heater.
I can now set the engine temp anywhere between the low 80's ºC all the way up to 108ºC.
Typically I keep it at 95/96ºC.

 

[4thBMW]

Thx Jim Lev...was trying to find that thread....

Yesterday, I boiled the105 deg C t-stat I had pulled out mentioned above....before I put it on the shelf. Thought I might see it open before 100 deg CI Lol, physics not cooperating. want to make sure all the air is out, think it is now, before making comparisons to this new like t-stat and what my drive around core engine temps say. *You can tell by the temps* if their is still air in the system or possibly a bad/ stuck t-stat.

 

[flemsmith]

Jim Lev, Although I admire your ability to do custom PWM upgrades, wouldn't the typical result you say you are running be the same as buying the 95C thermostat and terminating the heater connector with the 12ohm, 25W resistor I've read about previously? As long as I'm asking questions, seems like combining that thermostat option with the triple flow aluminum radiator would be a very good thing for Az summers, without having to get too technical...opinion?

Thanks, roy

 

[JimLev]

Flem, yes a 95ºC would work about the same. Some are using the 88ºC t-stat from the E39 Euro diesel engines.
I didn't have one on hand but I did have all the parts to build a PWM circuit.
I didn't need to bleed the cooling system either.
I already have a Zionsville radiator with a PWM speed controller on it. The fan circuit also keeps the fan running for 5 min after I shut the engine off.
The summers here just north of ABQ are probably about as hot as they are in Apache Junction.

 

[JimLev]

Yesterday, I boiled the105 deg C t-stat I had pulled out mentioned above....before I put it on the shelf. Thought I might see it open before 100 deg CI Lol, physics not cooperating. want to make sure all the air is out, think it is now, before making comparisons to this new like t-stat and what my drive around core engine temps say. *You can tell by the temps* if their is still air in the system or possibly a bad/ stuck t-stat.

Right, you can't get it to open in 100°C boiling water.
The t-stat will start to open at 103°C.

 

[Burning2nd]

212f-217f

 

[4thBMW]

Just drove 35 miles on a good coolant bleed @ mid-70's F ambient

....and rain. new105 deg C t-stat. works fine avg. 105 high 108; low 104 on accel under load...but seems to like 108 with that egg between my foot and accelerator 40-50 in town. My shrink advises me to turn off the temp. heads up and just look at the round temp dial. I forgot to mention above that BMW states that the cold coolant temperature when seeking the cold fill level with red stick in reservoir is 20 deg. C That ain't happening in my zip code till hell freezes over. So, if I see 29-30 deg. C one morning on test #7 before start up, I'll adjust reservoir coolant level down below the rim of the tank....thinking *pressure*....when running above mentioned temps.

 

[4thBMW]

Funny, I search : map controlled thermostat circuit and

See my 10 year old thread/post. Out of the blue now @ 176 k mi, started up yesterday and was misfiring with the check engine soon flashing. Pulled codes 8c (map controlled thermostat circuit); 32 (misfire cyld #1); and multiple misfires. Used the core eng. temp. readout to make sure I was staying in bounds of the 8c range and drove. I did change my thermostat, switch and plug not to long ago and the whole throttle control unit later....Odd, misfires. going to check all the plugs, connectors (connectors were change a while ago, plugs @ 96K mi.). Listened to the injectors...all sound as usual. No leaks. Cleared all the codes, started dead cold and immediately misses again...not bad enough I cant drive light throttle. Can't think at the moment will keep looking. When driving the core engine temp warmed up as usual, quickly this time of summer and stayed between 104-107 in light driving lower rpms....like it should.

 

[TheBigGuMan]

Flem, yes a 95ºC would work about the same. Some are using the 88ºC t-stat from the E39 Euro diesel engines.
I didn't have one on hand but I did have all the parts to build a PWM circuit.
I didn't need to bleed the cooling system either.
I already have a Zionsville radiator with a PWM speed controller on it. The fan circuit also keeps the fan running for 5 min after I shut the engine off.
The summers here just north of ABQ are probably about as hot as they are in Apache Junction.

I have the Zionsville heavy duty kit for e39 with 2-speed SPAL fan option. Was this PWM controller and option that Zionsville had available? If not, how did you actualize this PWM controller? I have an upcoming Vanos replacement and chain guide service planned and intend to move to the 88C thermostat. It would be a good time to update the control of the SPAL fan if available. Thanks!

Flem, yes a 95ºC would work about the same. Some are using the 88ºC t-stat from the E39 Euro diesel engines.
I didn't have one on hand but I did have all the parts to build a PWM circuit.
I didn't need to bleed the cooling system either.
I already have a Zionsville radiator with a PWM speed controller on it. The fan circuit also keeps the fan running for 5 min after I shut the engine off.
The summers here just north of ABQ are probably about as hot as they are in Apache Junction.

I have the Zionsville e39 Heavy Duty kit with 2-speed SPAL fan. I have to do an unscheduled chain guide service due to a hard Vanos failure and plan to replace the thermostat with the Vemo 88C model durng this service. I am interested in the PWM fan control you mention for the SPAL fan. Zionsville offers no such thing. Was this something you created? I would be interested in any details you could provide. I could go through the trouble to design and build one myself, but I am not convinced I would be motivated enough to do so. Thanks!