Author Topic: DIY Thermostat and Coolant Replacement (Read 55595 times)

Zoso · « **on:** March 10, 2006, 10:02:51 AM »

http://zoso.no-ip.org/318i-thermostat.html

m42 fan · « **Reply #1 on:** March 16, 2006, 09:28:27 AM »

Mike,
Did this wind up helping your fuel economy? I'm seeing almost the exact same indications out of my car right now. Temp rarely leaves the blue, poor heat on really cold days. At first I thought it might just be the guage, but the other day, when it was 75 outside, the temp went up to the middle.

I've been getting ~21 mpg in strict city stop and go driving and 26 mpg in mixed city/highway driving, and this looks like my next step. I already replaced the plugs, O2 sensor, fuel filter, and air filter.

Just wanted to know how that worked out for you, since you don't say on your page. Thanks
Brian

Zoso · « **Reply #2 on:** March 16, 2006, 09:48:16 AM »

I do believe that it helped my economy, although I never took the time to calculate the MPG before and after. After the new coolant and thermostat, I was able to go 400+ miles on one tank a few times.

Perhaps it is a placebo effect though... but better fuel economy makes sense. For the engine to run at it's optimum, it needs to be at a nominal temperature. Since I've gotten the new thermostat and blue BMW coolant in the car, it really stays a hair under or at 1/2 way all the time now. I suspect someone put an 80 degree thermostat in your car too.

The parts aren't that tough, but the procedure was somewhat of a pain for me since I couldn't get the fan off. With the fan off, this should be a snap.

The worst you'll do is normal maintenance on the car!

kowalski · « **Reply #3 on:** March 16, 2006, 01:35:22 PM »

hmm, well maybe ill adjsut the temp on my fan, let the engine get a littler warmer, maybe up to half or so..

nickmpower · « **Reply #4 on:** March 18, 2006, 09:11:35 PM »

Your thermostat is probably broken if it never leaves the blue. I have seen several cases where they have failed at around 130k miles. The one you get from the dealer is a new updated version.

do you happen to know the capacity of the system?

Zoso · « **Reply #5 on:** March 19, 2006, 05:40:16 PM »

Sorry, I don't know. The first time I put the system back together, I didn't seal it right so most of it fell to the ground. With all that spilled, and the 50% mixture, I still had enough with one 1G jug.

m42 fan · « **Reply #6 on:** March 26, 2006, 02:29:30 PM »

Finally got around to taking care of this today. It looks like the thermostat was my problem. After a test drive it looks like my temp is between 1/2 and 3/4 on the gauge I'll report back in a couple of weeks on my mileage.

Brian

Zoso · « **Reply #7 on:** March 26, 2006, 07:04:46 PM »

Nice.

Did you take your fan off or did you squeeze yours in between the fan blades like I did? If you did take the fan off, what tool did you use?

m42 fan · « **Reply #8 on:** March 26, 2006, 07:39:58 PM »

I wasn't able to get the fan off either, although I really didn't try very hard, since all I had that size was an adjustable wrench. Belive it or not, I wound up taking the whole radiator out. It came out a lot easier than I thought it would. So far no leaks, but I'll be keeping an eye on it for the next couple of weeks or so. Thanks for the help, btw.

Brian

twinpop171 · « **Reply #9 on:** March 26, 2006, 10:05:40 PM »

Quote from: Zoso

Did you take your fan off or did you squeeze yours in between the fan blades like I did? If you did take the fan off, what tool did you use?

I used a large adjustable wrench with a long cheater pipe when I did my water pump and thermostat last summer. It was still a bitch to break loose and a little scary praying that nothing slips.:eek:

FYI my temp stays just below the 1/2 mark.
Dan.

m42 fan · « **Reply #10 on:** March 28, 2006, 10:03:23 AM »

well, after driving the car for a couple of days now, it's evident that I have a leak. It's on the drivers side near the expansion tank somewhere. Here are a list of everything it could possibly be:
1) the cap
2) the bleed screw
3) the drain valve
4) the hose that conects to the radiator on the bottom on that side

What I've done already: I made sure and retightened the drain valve, and I took the lower hose, made sure it was on good, and retightened the hose clamp. Leak still exists. Suggestions?

m42 fan · « **Reply #11 on:** March 28, 2006, 05:39:05 PM »

I may have found my leak. Just for the heck of it, I took out the bleed screw. I didn't even realize it was there, but there is an o-ring there that I hadn't put back properly. I'm going to wait and test drive it to PT tomorrow morning. (0430 hrs.) I'm sure everyone will be up early awating my results!

ak96ss · « **Reply #12 on:** March 28, 2006, 05:50:29 PM »

Man, you guys do PT late... must be a Navy thing...

j/k

Go Army!

m42 fan · « **Reply #13 on:** March 29, 2006, 08:03:41 AM »

still leaking...

Zoso · « **Reply #14 on:** March 29, 2006, 08:05:19 AM »

That sucks.

Can you see any cracks along the plastic neck of the radiator? I know they are known to break in the E36 world.