cap/rotor question and overheating question

hpcbmw · Post by **hpcbmw** » May 8th, 2007, 1:14 am

Problem - car is getting very warm (3/4 way up the gauge) when driving over 70 mph. Happens when 90 degrees out and 60 degrees out, no uphills, also getting warm when idle. It seems to get better with a/c turned on, but not sure if that's just coincidence (haven't had much time to test it).

Just before this, the car ran fine, til i steam cleaned the engine, changed cap and rotor and hooked up extra neg and pos battery cables.

Problem 1 - when I took off cap and rotor, i got distracted and didn't check the old ones. Is there a way to tell if the rotor is on wrong? First try, it wouldn't start, so i moved it to second position and it seems to run fine. Can it run in two of the three possible positions? Possible I have it in wrong position and the timing is way off? Car starts right up and runs strong (seems normal).

Problem 2 - Can the distributor cap go either way? Is the breather/vent on the cap pointing up or down? Does the number one plug wire connect to the "1" stamped on the cap?

Problem 3 - is there a temp sensor that turns on the fan that might be getting a poor connection? When I stopped and checked, the cooing fan was on at idle (and the car didn't overheat). With a/c on, second cooling fan cycles off and on (approx 3 mins on, 1 min off). The temp gauge was in normal (center of scale) when checking this.

I added the ground wires and a positive wire direct from battery to alternator to try to fix low idle (close to dying when headlights on and hit brake pedal). The additional wiring made no difference (although headlights might be a bit brighter).

Sorry for the long and convoluted posting. Thanks for any help. If my girllfriends mx-3 overheats on her, after I "fixed" her car, i'm sleeping on the couch!

Bumpysbro · Post by **Bumpysbro** » May 9th, 2007, 5:11 pm

hows your coolant level? and when was the last time you changed it?

for problem 3: there is a coolant temperature sensor and a temperature sender unit that goes to your dash. i had a overheating problem about 5 months ago and the problem was there is a fan relay under the overflow tank on the driver side that when the car gets to a certain temp it kicks it on. well mine had water on the relay and it wouldnt kick the fan on or maybe your relay is bad.

problem 2: with my car i have a dohc so not so sure if you got a sohc or not but with my cap it goes on only one way, theres a hole for the secondary coil tower so the cap can go on only one way. hope that helps
Jon

hpcbmw · Post by **hpcbmw** » June 13th, 2007, 1:53 am

"for problem 3: there is a coolant temperature sensor and a temperature sender unit that goes to your dash. i had a overheating problem about 5 months ago and the problem was there is a fan relay under the overflow tank on the driver side that when the car gets to a certain temp it kicks it on. well mine had water on the relay and it wouldnt kick the fan on or maybe your relay is bad."

Where are the coolant temp sensor and temp sender unit? What does the fan relay look like? The car only seems to heat up when rpm's over 4000. Do you recall the part number for the fan relay, and/or the cost?

Thx

Bumpysbro · Post by **Bumpysbro** » June 13th, 2007, 5:20 pm

i actually didnt replace it, the fan relay is under the coolant resevoir and in a little compartment below it and above the fender. its black and has wires going it, i just dried mine off and sprayed electrical spray on it and seems to fix it. the coolant temperature sensor is on the head next to the thermostat housing. if you go to the online shop manual its section E1 and page 009. its that sensor to right of it. and the temperature sender which sends the temp to your dash is on the front of your head to the right of your exhaust manifold and under the coolant hose. if you think its your radiator fan thats not turning on when it gets to that high of a rpm you can go to F1 in the manual and page 144 shows some diagnostics to check if your coolant fan is working properly. best of luck
Jon

hpcbmw · Post by **hpcbmw** » June 13th, 2007, 11:35 pm

Can someone link me to the shop manual? I've found it once, but forgot to bookmark it. Thx

Cy · Post by Cy » June 14th, 2007, 1:53 pm

if nothing seems to fix this.... a last resort would be to install a lower temperature thermal switch...having the primary fan kick on sooner..

hpcbmw · Post by **hpcbmw** » June 25th, 2007, 12:05 am

after all that, it turned out to be just a bad thermostat.