| Home  Blogs Help Search Login Register  
« previous next »
Pages: [1] Print
Author Topic: Water temp sensor  (Read 2432 times)
Anders Dinsen
Administrator
YaBB God
*****
Posts: 2823



WWW
« on: August 30, 2009, 10:25:04 pm »

I've had an annoying problem for the last couple of weeks: As the engine warmed up, the water temperature started dropping. Not consistently, but suddently it would drop below the 70 degrees mark. Then back up a bit. Then down to 50!  Shocked

It was driving me mad.. Is there a air trapped in the system? A leak? Is it boiling? Am I damaging the engine?

I decided, however, that it was an electrical fault. The sensor was new - well only two years old, so I could rule out that and start looking for other problems.

So I cleaned the grey wiring loom connector next to the fuse box. I also carefully checked the wiring measuring resistance from either end. All OK!

Ground connection could be bad... Well not really, because then the oil pressure meter would have shown a similar pattern, which it did not.

Water leaks? Nothing. Check again: Still nothing.

So yesterday I replaced the sensor anyway. I had an old one that had come with a thermostat housing. I think it came off the car that we stripped last year with Waldo. With a busy weekend schedule, I didn't have time to try it out before now, and I have just returned from a test drive. IT WORKS! The engine warms up nicely, then stabilizes around the 70 degree mark, only slowly climing halfway to 90. The completely stable. Impossible to drive up in hard (really hard!) driving, or idling. Just perfect!

I guess the morale is: New parts DO fail. It will be interesting to see how long the new (old) sensor will last!

/Anders
Logged

'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
Oetker
YaBB God
*****
Posts: 1048



« Reply #1 on: August 31, 2009, 08:29:20 am »

I had something simulair, but in my case it was a problem with the connector on the right in the enginebay.
The yellow/blue wire had some oxydation on the spade plug in the connector.
I am gonna replace this connector for a superseal connector.
It was not the first time I had a problem with it.
Logged

I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
Anders Dinsen
Administrator
YaBB God
*****
Posts: 2823



WWW
« Reply #2 on: August 31, 2009, 04:43:17 pm »

I had something simulair, but in my case it was a problem with the connector on the right in the enginebay.

That was what I thought too originally, especially as the green connector housing was well melted around the starter wire. But the new wiring loom and new connector which I fitted about two weeks ago didn't help. See http://gallery.dinsen.net/v/biler/Matra/technical/electrics/wiringloom/

A water proof connector is a good idea, but I personally don't like the AMP superseal connectors. They are a pain to work with. Maybe it's just my ten thumbs? So I have fitted a modular connector similar in layout to the old one:



It may not be better than the old one, but its new, and I can live with it lasting only 20 years as the old one did Wink Besides, I've filled it with silicone grease, so it should be okay for a while!

/Anders
Logged

'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
Oetker
YaBB God
*****
Posts: 1048



« Reply #3 on: August 31, 2009, 05:00:16 pm »

silicone grease Shocked
Accid free I hope, otherwise youre new connector cupper spades will oxidate very fast.
I fill them with white hand cream pure vaseline (don't know the english word).
When the connectors are mounted make it a bit warm, so it melts over the spades.
Before you put on the connector pull a finger of a rubber glove over the  wires and when the connector is mounted pull it over the connector.
This wil be pretty watertight.
Logged

I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
Anders Dinsen
Administrator
YaBB God
*****
Posts: 2823



WWW
« Reply #4 on: August 31, 2009, 07:44:04 pm »

silicone grease Shocked
Accid free I hope, otherwise youre new connector cupper spades will oxidate very fast.

Absolutely acid free and does not mix with water at all. It even resists oil, fuel anything. I suppose it has a boiling point, but I don't know it. And it's easy to wipe away, non toxic (even food approved!) etc.
http://en.wikipedia.org/wiki/Silicone_grease
Logged

'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
Pages: [1] Print 
« previous next »
Jump to: