Trouble With M3 In The Heat?

Car: E46 M3 2003 SMG Vert

Trouble: Last weekend it was 40+ degrees and i noticed the Oil Temp go to about 115-120 degrees celsius. I also noticed the Water Temp rise to the dot on the right. They then went down after a bit of cruising on the freeway. I was driving to a destination about 1.5hrs away.

I noticed when I turned the car off at the servo, the temperature was in the middle of both the Oil Temp & Water, when i got back to the car and turned it on, it had risen back to the same levels that i mentioned above. Then after a bit of driving it went down again.

I then noticed the Oil Temp & Water Temp issue to happen again today, it was about 37 degrees celsius, i had the aircon blaring and was driving for a while, then the SMG light came on and stayed on. Then the gears were going into neutral as i was driving. I took it to the mechanic who checked it and he said it was a sensor from the heat. Then i checked this: http://www.e46fanatics.com/forum/sho...d.php?t=855810

In the book for the car it says that the car is fine to drive anywhere just as long as it's not in the blue or red zone. It says the temperature may rise and drop but as long as it's not in either of those zones it's ok.

So has anyone had any of these happen to them before?

1) Do i have a problem with my cooling system or am i over reacting and it's just the heat? Car goes into service and i will be doing a coolant flush/bleed. It's been 10 000k's since last service.

2) Is that link i posted what is the cause of my SMG problem?

Any info would be good, thanks guys.

It really depends on how you were driving it. I've found that with spirited driving I can get the oil up to 110-120, water temp doesn't usually rise but it did the other day in extreme conditions. 40 degree day, driving up hills, trying to keep up with a 360, 430, 35GTR etc., windows down and AC on 16 with full fan. I was also holding gears for longer than necessary so I'm pretty sure that was the cause. I haven't been able to replicate the issue since.

Oil and coolant temps will often spike if you turn the car off as the fluids aren't being circulated as they usually would. It's for that reason that I never turn my car off when the oil is above 100 apart from when the scenario mentioned above where I pulled over as soon as the coolant got hot and turned her off for 20 minutes. I generally try to coast at low revs or even neutral for a bit after really spirited driving and that cools the engine down pretty quickly.

I've never had the SMG issue but have read about it before and the resistor seems to be a well supported solution so I'd give that a go. I had thought about doing it but I'd rather not go put resistors in my car when I haven't had the issue. As soon as I have it I will follow the DIY you linked to though.

In short, if you were driving hard then the temps described sound normal on a 40 deg day. If you were cruising then the temps shouldn't spike like that and I'd look at changing the fluids if they haven't been done in a while / were replaced with non OEM fluids. If you weren't driving hard and have new fluids then something's not quite right.

Yeah i have to admit i was pushing it a bit, especially today. I had the air con on 16 aswell and stop start, spirited driving etc.

The SMG issue has only happened once (today), so should i do the resistor method? Or wait if it happens again?

Also, i'd be happy to pay someone to do the mod for me, lol i don't trust myself doing it hahaha.

Here's the DIY for it http://www.m3forum.net/m3forum/showthread.php?t=372262

They get hot in the heat with the a/c on. Mine does too and I thought it was just cause I got a dirty big intercooler in front of everything. But no they all get hot with the a/c on in heavy traffic in 35+ weather

In my car both needles stay pretty well permanently glued to the centre of the dial, outside temp goes under 25 and the water temp needle sits slightly left. Get to 40 or so outside, AC on, and the water temp needle will lean just slightly right of centre. Only time when my water needle has risen right up to about 3/4 mark was when it was 44 outside, AC on, stuck in heavy city traffic.
I got my coolant flushed about 20K ago.
If you really want to bulletproof your coolant system head down the Zionsville route. Plenty of guys whot street/track/race with them, and swear by them, (rather than at them) Guaranteed for life for street or race use...

http://www.zionsvilleautosport.com/s...ode/CCSE46.htm

Originally Posted by kook

In my car both needles stay pretty well permanently glued to the centre of the dial, outside temp goes under 25 and the water temp needle sits slightly left. Get to 40 or so outside, AC on, and the water temp needle will lean just slightly right of centre. Only time when my water needle has risen right up to about 3/4 mark was when it was 44 outside, AC on, stuck in heavy city traffic.
I got my coolant flushed about 20K ago.
If you really want to bulletproof your coolant system head down the Zionsville route. Plenty of guys whot street/track/race with them, and swear by them, (rather than at them) Guaranteed for life for street or race use...

http://www.zionsvilleautosport.com/s...ode/CCSE46.htm

Try cranking the AC on 16 on a 40 deg day whilst having the windows down and driving hard. That should get that needle up there. I don't encourage it though...

I use to drive the 325 hard on twisties with the AC on 16, windows down (sorry Brett!) and never had any issues at all. I guess it's just the highly strung S54's that are prone to the problem.

Yeah, both occasions was due to spirited driving.

I'm flushing the coolant and replacing it with genuine BMW coolant, so we'll see how it goes after. This has never happened because it's not usually extremely warm here.

Yeah these cars get hot. I get the needle in the centre of the dial cruising on the highway with the a/c on in 40 degree heat. lol

Yeah.

With cruising it's fine, it's more with spirited driving the needles move a bit.

Sounds totally normal to me mate.

Oil temp is always slightly high after restarting a hot engine (oil stops circulating). Everything else sounds like the engine doing it's job. It has been hot as hell lately. I've read somewhere that it's good to get your oil temperature up in the 100s + every so often as it burns off any water therein.

Originally Posted by launch

Sounds totally normal to me mate.

Oil temp is always slightly high after restarting a hot engine (oil stops circulating). Everything else sounds like the engine doing it's job. It has been hot as hell lately. I've read somewhere that it's good to get your oil temperature up in the 100s + every so often as it burns off any water therein.

Yeah it has been pretty hot.. last weekend was 43c and i was giving it a bit of a hard time. Then yesterday was 37c. I was just a bit worried cause it's not often that hot around here lol.

Do you think the heat would've contributed to the SMG issue aswell? I took it and had the diagnostics read by the mechanic and he said it was a sensor. Could it be because of the heat?

Originally Posted by M3N7AL

Do you think the heat would've contributed to the SMG issue aswell? I took it and had the diagnostics read by the mechanic and he said it was a sensor. Could it be because of the heat?

The link you put in your original post sounds like the text book answer for the SMG problem. I'd never heard about it until then. Great cheap easy fix for that. The mechanic's diagnosis seems to back it up (sensor failure).

Awesome. Thanks mate

Does anyone feel like doing the mod for me? LOL Happy to pay some $ or donate a 6 pack of beers hahaha.

I never had temp issues with my 02 M3, the water temp gauge sat just left of centre and when it was 40+deg outside it would sit in the middle. I never push my cars on hot days though. The oil temp would sit just past 100deg on hot days.

In my current 06 M3 the water temp gauge moves around a lot more, but anywhere in between the two dots is fine both on water and oil temp gauge, pushing past the second dots would not be good though.

As i mentioned in a previous post r.e. vanos, i replaced all the belts so that they were driving the water pump effectively, i replaced the fan clutch as well because that was fux0red. Its as good as its going to get.

I've read about people replacing the temp sensor resistor or something r.e. SMG failing on hot days - i am unsure about this and haven't had it done. Touch wood i haven't had my SMG play up on hot days at all - i have replaced my salmon relay as a preventative measure though.

Speaking with CortinaD put my mind at ease too as he experiences the same issues. I suppose the thing to do is not pants it when its hot, and if you are delivering a LOT of punishment to it for long stints, short shift and don't wring it out to 8000rpm in every gear.

I still don't believe that your car should EVER move from centre. The way modern cars are built, there shouldn't be a single situation short of sustained abusive track use that would cause any sort of movement in the temp gauge.

Originally Posted by trive2

I still don't believe that your car should EVER move from centre. The way modern cars are built, there shouldn't be a single situation short of sustained abusive track use that would cause any sort of movement in the temp gauge.

I wouldn't call the E46 M3 'modern'. Whilst I wouldn't like my temp to move from the centre, I can understand why an engine like the S54 which was developed to extract almost as much power as possible from a NA 3.2L engine could be susceptible to some heat issues in extreme conditions (AC, 40deg days, being driven hard).

It's not like they are overheating and pissing out coolant. They are just getting a bit warm when they are under stress.

When I went on my track day I didn't use AC and it was 30ish degrees outside. I had no issues with heat there. It just seems like adding the extra stress of a few degrees in external temp and a 10yr old AC system working overtime causes things to get a bit hot.

Not to mention it does say in the book that the cars oil and water temp will fluctuate and that it's safe to drive when the water is anywhere except the blue/red zone.

Got a call from the workshop today about the car as it's being serviced there and they found out why the car was heating up.

Water pump was stuffed. It's being replaced under warranty along with the belts. Now i know why i've been hearing a slight whine lately. Could this have cause the car to lose power aswell?

Stuffed water pump will cause high temps and no, the pump itself will not cause a power loss.
The whine could be your power steering system though.

Thanks.

I searched online and the whine is a symptom of stuffed bearings in the water pump.

I'll have to wait and see tomorrow when i pick it up.

Should pick it up tomorrow