Author Topic: Hello, would you like to help with my cooling system battle? (Read 3756 times)

Rosales · « **on:** April 07, 2010, 07:51:18 PM »

I came across this site recently and it has been a great source of info so far. I've posted my issues on two other bmw forums with little to no help, so maybe since you guys can help me out.

I have a m42 94 318is with the engine from a 92 installed. I got it in high school & had it running well for a few years. One day though it began to overheat on me. This made me realize That I was a stupid kid and really didnt focus on the cooling system like I should have.

So for the past 2 years the car has been my project and Im hoping to get it up and running better than before. I have purchased and installed the following items (new of course):
-Radiatior
-Upper & lower radiator hose
-Thermostat
-Water pump
-Black coolant pipe under the intake
The only thing I can think of that I have yet to replace is the thermostat switch on the side of the radiator.

When I tried to get it running the car would idle up to 25 min and not overheat, but once I drove it down the block the temp gauge would begin to move up. The car isnt loosing coolant nor does it display the traditional traits of a blown headgasket. Ive attempted to bleed the system many times and even got the heater to blow HOT while doing so. Some people say that it may just be air left in the system but Im not positive on that.

You guy seem to have more know how on these engines, So your imput would be greatly appriciated.

Thank you and sorry for the 1st post novel

Romrog318is · « **Reply #1 on:** April 07, 2010, 08:16:12 PM »

it might not be over heating at all check your temp gauge and engine temp gauge...

also ive come across a few thermostats that were bad...

and does your fan work well?

Ryann · « **Reply #2 on:** April 07, 2010, 08:41:37 PM »

+1 "it might not be overheating".. It is way more likely to overheat while idling that while moving.

dinu.negrean · « **Reply #3 on:** April 08, 2010, 04:15:50 AM »

It is easy to check is the themostat is working or not, check the hooses to see is the temperature is even on both sides.

Check also the waterpump. Remove the tap of the radiator, and right on the neck on the radiator side, you have a small hole. As your revs go up, pressure in the system is increased and more water should come up that hole. It starts around 2500-3000rpm.

It is more likely to overheat while idling but it's not normal at all.

How did you bleed your system exactly? I have met a similar problem and it was just the cooling system wasn't properly bled. After bleeding it right the problem has dissapeared.

Rosales · « **Reply #4 on:** April 08, 2010, 09:45:19 AM »

I tested the thermostat the old drop it in boiling water way and it did open up like it should have so that seems to be in working order.

When it comes to the fan, the clutch fan was installed and that worked, but i recently went on a junkyard run and picked up an electrical volvo fan to intall so ill see if that works. The aux fan up front wouldn't turn on so I got lucky and picked one of those up too.

I THINK the temp guage is in working order, but to be honest im not exactly postive. How would I go by checking that?

When it came to bleeding it I followed the pelican parts method but also did the elevated front end way. So any guides where I should go from here?

monko141 · « **Reply #5 on:** April 08, 2010, 11:27:52 AM »

The procedure I use is,
1. Take off upper radiator hose from radiator, loosen it at the head, spin it upwards and re tighten it on the head.
2. Remove radiator cap and bleed screw.
3. Turn on ignition switch, turn heater controls on.
4. Pour coolant in upper radiator hose until it spills out of radiator cap.
5. Install radiator cap and pour more coolant in upper hose.
6. Place paper towel over upper hose, blow into upper hose, add more coolant until coolant flows, without bubbles, out of bleed screw hole. (blow slowly, you are filling the radiator through the small hole that is in between the radiator and the expansion tank)
7. Install bleed screw, pour more coolant in upper hose until it over flows.
8. Re install upper hose on radiator.
9. Start car, take for a test drive.
10. Check for leaks while the car is warm, let cool and check coolant level in expansion tank.

This procedure worked on both my m42's and my m50.

Rosales · « **Reply #6 on:** April 08, 2010, 12:56:32 PM »

Thanks for that method.

Just to be on the safe side before I get started, are there any new or other parts I should get before attempting this again?

cristimm · « **Reply #7 on:** April 09, 2010, 03:59:34 AM »

To make the bleeding easyer you could drill a small hole in the thermostat. More info here:

http://www.miracerros.com/mustang/thermo.htm

Ryann · « **Reply #8 on:** April 09, 2010, 10:53:55 PM »

This has worked for me twice after the system was completely drained:
1. Prepare 7 qts. of your preferred antifreeze and water mix.
2. Fill the reservoir until it won't take any more coolant.
3. Start the car, turn the heat on, and go back to keeping the reservoir full.
4. When the level in the reservoir stops dropping, grab the upper radiator hose and squeeze it firmly/repeatedly (mind the fan) until the level starts dropping again.
5. Repeat until all 7 qts. have been added.

The key here is adding the specified quantity.

Phreon · « **Reply #9 on:** April 11, 2010, 03:37:06 PM »

I had to bleed mine as Ryann posted above. Also when you reinstall the thermostat it has an arrow that needs to be pointed up.
P

Rosales · « **Reply #10 on:** April 11, 2010, 06:03:17 PM »

I did know about the thermostat and the arrow, but I think I made a stupid error by squeezing the bottom hose instead. Thank you guys and I'll give it another shot soon.