Nother 62tu 88C thermostat data point

[paul p]

Since Björn was throwin the codes, and ECS also had not stupid priced Mspec pork chops, took the plunge on the mod. Was hoping to see operating temps do the same.
Sorry BMW540san, if you had an active sale, I missed it.
Still annoyed that I was replacing a failed OEM part after less than 4yrs.

Install wasn't bad. Pulled the intake and popped off the mechanical fan. Considered removing the air crossover pipe but was able to work around it w/ a ratcheting box wrench. Would have been a bear w/o it.
Fortunately the radiator hose reseated nicely, no leaks.

After adding a little over 3/4gal and bleeding, came up to temp much faster. Bout 5 minutes idling, 80c according to test7. Ambient was 65F here.
Getting on the highway temps were very consistent @ 96c. Playing around w/ HVAC would move it a degree or two around that, but it would settle back in less than a minute.
Simulated stop and go round the hood and still stable.
Nose in to the garage, alternating max 60F A/C and all off did make it climb to 99c. But then it sat right there for over 5 minutes before I decided it was time for a cocktail.

No resistor, no SES light, and no drivability issues.
We'll see if mileage changes. Hardly the point w/ 4.4L v8 anyway.

[Kenny1958]

Nice info

[BMW540san]

No problem. It's been few months since I sold my last one due to my supplier in Europe raising prices considerably.
Now the prices are down again. I could get a half a dozen more and sell them $85 each with free shipping if bought through here.

[scottieducati]

Will finally be installing mine when reassembling after timing chain and guides job.

[geargrinder]

Will finally be installing mine when reassembling after timing chain and guides job.

Alright alright! Look who's here. Hey do you need a MAF resistor? I assume yes. I should have one lying around.

[scottieducati]

Ha, you tell me.... I'm guessing yes, I do need one....

[paul p]

Next day, we were about a pint short and done. Fully bled it seems.

Temps very consistent. Couple of degrees from 96c, depending on conditions, max

Will be doing the same to Gerta very soon

[paul p]

Have to admit. BMW engineers still had some sense.

Borrowed das Kinderschleppen to commute. I deserved it considering that she got an oil change in addition to the wash. And vacuuming up tons of toddler trash.
She doesn't have the 88 mod.
Kept a running log of temps.

While the system allows 110C+ coolant temp when it isn't stressed. It's impressive to see it compensating when you're stuck in 10mi of stop and go traffic, in almost 100F ambient temps.
And blasting the a/c.
Between the aux engine fan cycling a lot and probably some thermostat trickery by way of the sensor/heater. She kept totally cool w/ cluster temps of 97-100C.
Not bad. Still seeing <100C all the time would be better.

[geargrinder]

Nice. Rare kudos to the MAP system based on fact based observashunz. Like it. I think the engineering idea is solid and unlike some I know the science says hotter engine temps = more power and efficiency (and not just in the 'gas mileages sense). Interesting that it seems to activate more than the documentation suggests... one knock on the system is that the doc implies that it only comes on at WOT / high load, and therefore how could it respond fast enough or often enough to make a difference. But perhaps it uses ambient temps to activate more often / longer than the doc implies? Like 'when hot out run cooler'?

That still doesn't mean the lower temps aren't better for wear and tear on soft engine parts (hot temps are better for the hard metal parts which is where the better efficiency comes from) and so I still think for a hard driven M62 a temp mod isn't inadvisable.

Related - I noticed I got the MAP cooling error yesterday and will post more about that later but I've been wondering if that was from our triple-diggy temps 2 days ago... gotta run but more later.

[paul p]

Nice. Rare kudos to the MAP system based on fact based observashunz

Thanks GG. Day job is running a wastewater analytical chem lab, lots of auto instrumentation.
Can't help it.

Interesting that it seems to activate more than the documentation suggests... one knock on the system is that the doc implies that it only comes on at WOT / high load, and therefore how could it respond fast enough or often enough to make a difference.

It actually does do this. Had the cluster Test 7 running, and watched temps dip when getting aggressive w/ the throttle, often below 100C. In something like 5 seconds.
Stays there for a couple of minutes even if throttle application is light from then on.
You can actually trigger it by just revving the car, even parked. Used to do this in Bjorn all the time before 88c.

But perhaps it uses ambient temps to activate more often / longer than the doc implies? Like 'when hot out run cooler'?

Obviously some of that going on. Since Gerta is auto and I was lazy, didn't do any revving to try and trigger. Just went with the flow.
And the temps just kept under 100 the whole time

That still doesn't mean the lower temps aren't better for wear and tear on soft engine parts (hot temps are better for the hard metal parts which is where the better efficiency comes from) and so I still think for a hard driven M62 a temp mod isn't inadvisable.

More so for a home maintained bimmer mill regardless of if it's driven hard.
88c unit en route.

[Mach540]

If someone cared to really geek out, they could wire up an LED light from their dash to the thermostat heater and monitor the operation.

[Bruce SEA 993]

Did you go with a lower pressure cap?

Besides the lower temp, it seems that the pressure is another stress point in the system.

Cheers!

BTW, looking for the part number for the cap if lower temp (88deg) thermostat and cap would work together

[Mach540]

Lower pressure cap does not affect cooling system operation. It is only a failsafe for an overheated situation

[geargrinder]

Lower pressure cap does not affect cooling system operation. It is only a failsafe for an overheated situation

Times 10000.

And having an excessively low fail-safe pressure in the case of a minor cooling system fault really isn't helpful, only increases your chance of being stranded roadside when otherwise the car probably would have made it to a safer / better / cheaper / easier place to breakdown / cooldown, except that your low pressure cap puked all the coolant onto the ground...

But lets not go back down the "you guys are dumb all I know is if I put a lower PSI cap on my system will be lower pressure!" rabbit hole PLEASE.

[Bruce SEA 993]

Oh OK, I always thought that the cap allowed the coolant to have a higher boiling point....besides acting as an escape valve for over heated and over pressured coolant.

These cars run at a temp over the boiling point and have a 2 ATM rating for blow off.

[Mach540]

You are exactly correct. The pressure does increase the boiling point.
But only to the point that the cap begins to release pressure.

[Bruce SEA 993]

I want to change to the 88 deg thermostat...was wondering if the cap goes along with this mod.

Also, paul P (the OP)...in your write up, you said you removed the fan...did you do that for access or removing it for good with this 88 deg thermostat?

BMW540san...are you going to bring more 88 deg thermostats in? I would o for one. Thanks!

[Mach540]

No cap..... just thermostat change.

You "can" leave the fan off if you want, but if you are at all unsure or uncomfortable with that, leave it on.

ECS is supposed to have more in stock in July, but I wouldn't count on it.

[JimLev]

Removing the fan is a crap shoot at best. If your aux fan fails your screwed.
Some peeps have run with no clutch fan for years without problems, others called a tow truck, it's your call.

[paul p]

Also, paul P (the OP)...in your write up, you said you removed the fan...did you do that for access or removing it for good with this 88 deg thermostat?

I only removed the mechanical fan to gain access during the install.
As soon as I saw that the o-ring on rad hose wasn't leaking it went right back on.

Kept the stock cap.

[geargrinder]

Jim knows all this but I removed it with stock Tstat, supercharger, AC on, triple digits temps. No issues. Now 88C Tstat and even less concerned been (obv it goes on far less often now). I've said before running just the aux I probably WILL proactively replace it soon at a convenient time. But it's been rocking and rolling for years now - ever since I did the blower. Totes fine.

I'm not running around telling everyone to do it but neither do I think it's a huge issue or massive chance of stranding . Any fan in the world does nothing over 30-40mph so if you have a fan failure as long as you can limp home w lots of highway and no traffic jams even that's not a huge deal. Car runs fine with zero fan in fact at triple digits Fahrenheit as long yer moving at least that speed.

[paul p]

I did do a 3 season mech fan delete on Rolf our former 92 325. Still didn't risk it in summer after a somewhat hairy hot commute. Official outside temp was 98F, car was saying 116F (pavement temp at that point) Noted the gauge creep up a tick or two and hover while blasting the a/c. Turned it off, popped the windows and roof and it settled back down. A few blocks later the clot cleared and it stayed stable w/ a/c the rest of the way. Double checked coolant level and bleed that evening.

The mod was more than just a lower temp thermostat too. There was also a lower temp 2 speed switch for the pusher fan that screwed into the radiator.
It was a more noticeable mod on that car anyway. The M50 non TU was a little peaky and you really could feel the parasitic drag of the mech fan, specially w/ the a/c full cold and the car loaded. The m62tu has more than enough torque to compensate in most cases. W/ 2 kids and just my wife in the car often enough, I'm trading a tiny bit of possible performance for the security of 2 fans.

[geargrinder]

My reasons are not "parasitic power loss" oriented whatsoever.... it's probably a combo of...

1. No assploding fan or soft-motor-mount-hood-strike worries
2. Front of engine access... and with the blower you have to use this fan extender that pushes it into the shroud to clear the new belts which just makes things more PITA
3. Originally at least... Laziness. Put the whole blower stuff on, but was dicking around w/ belts and whatnot for a while so I left the mech fan for last / later, and even had planned an aftermarket electric puller - I even have the controller box for it on the shelf... but as time went on and it was clearly 100% fine, I had hard time justifying the time to do a new fan project, and, then losing out on #2 above when it was done.

So - mostly its a reliability and simplicity mod for me.

[Mach540]

I plan on leaving my mechanical fan off after I replace the AUX fan. But I'm also seriously considering a backup puller fan.

Mostly cuz I hate the school bus whooshing.

[paul p]

My reasons are not "parasitic power loss" oriented whatsoever....

Like I said, that was an issue on a on a 2.5L M50 NON vanos, you kinda needed to wind out that puppy to get power. Not so w/ a stock M62tu
I can only imaging 4.4L blown having an ..... excess of torque available.
If I'm reading correctly you don't even have a/c either?