1989 300TE need confirmation before buying parts
 

Its been a joy working on my 1989 300TE. Winter is coming and I am getting ready to leave the Honda S2000 in storage until next summer so i am in a hurry to get all these little issues fixed on it. I would appreciate any advise/confirmation before i go out and buy all these parts to see if i am on the right track.

Issue 1.

Coolant temperature instrument sporadic behavior. the needle will climb smoothly, and idles at 80C. the needle jumps up and down (sometimes it pegs out the gauge) i will do this at idle, and on the freeway cruising.

I am assuming this is the coolant temperature sensor. i see 3 sensors located on the top of the engine. the one closest to the firewall is the engine temp sensor the middle one is for the instrument and the last one is the aux fan control? i should be able to replace the middle sensor and fix the jumping needle problem.

also the research i have done is you can unplug the last one (closest to the front) and the aux fan should come on max to test if the sensor is working.

Issue 2.

The Oil pressure gauge maxes out. when the car is off it is at "0" position, as soon as i turn the ignition on it maxes out, i assume the sensor is bad. can anyone advise where this can be found and if my assumptions are correct?

thank you all for any advices before i start buying parts left and right. This forum has been great for all the Mercedes i have own and really does make owning these older Mercedes a joy when these is such great support to keep them running right.

Oil pressure sender is on the oil filter housing. One wire attached.

Easy enough to remove after taking oil filter off; but there is not much room to work.

the temp problem sounds like a ground issue with your cluster, or a bad wire.

The coolant temperature sender on the head for the cluster is the single wire one. My connector cracked when I replaced the head, and I had to do a rush solder repair job on it later on. Symptoms were as you describe. I properly repaired the job and it works great now.

can you describe what you did to properly repair the connector? I need to take a picture tomorrow but i noticed on one of them the connector was in a rough shape, i didn't think this was the instrument cluster sender so i ignored it.

also do they sell replacements? i couldn't find any one peachparts.com

thanks

My repair was with the wire connector end (simple soldering job), not the actual sensor piece. If you search the parts catalog for "sensor", it should pop-up. Single pole connector as I said.

I have the same issue you describe with my needle. Whacking the top of the dash corrects it. I'm suspecting a cluster issue because I have some other symptoms. If it's below 40degrees it takes a couple minutes for the cluster lights to come on. If a new sensor solves it, let me know. Be good to have an answer.