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3.5 Water temp drops

Posted: Tue Apr 19, 2011 12:00 pm
by Bosbok
Hi guys I just want to know what can be the reason for my Pajero water temp dropping when i free in gear down a long down hill and is this normal, or is my thermostat faulty and not closing like it should

thanks
Bosbok

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 12:22 pm
by 4ePikanini
once the car is at operating temperature, nothing should make the temp needle move in either direction. It should be completely stationary at all times.

If not, it is either a bad sensor, bad gauge or faulty thermostat.

See this thread for testing

https://www.pajeroclub.co.za/forum/viewtopic.php?t=1512

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 12:26 pm
by 4ePikanini
How old is the thermostat?

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 12:54 pm
by Bosbok
Well I bought the Van last year but i would say probably as old as the van it self but . the gauge never move if i am driving in a normal situation only when going down long pass and a anther thing is if i drive with the heater on it seems like the car does not want to reach operating temp

Thanks for the coments

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 1:11 pm
by 4ePajero
All the symptoms point to either an absent or a stuck open thermostat.

Over-cooling is nearly as bad for your engine as over-heating!

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 1:19 pm
by Bosbok
Thanks i will replace the thermostat and check if that solves the problem . why do you think someone will remove the thermostat

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 1:21 pm
by 4ePikanini
It is probably a thermostat that doesn't close properly. Mitsubishi's and Volkswagen thermostats are designed to fail mostly in the open position rather than the closed position.

How long does it take to get up to operating temperature?

Should you wish to replace the thermostat, make sure you get the right one. Use these part numbers

MD174233 - 1993 - mid 1997
MD348937 - mid 1997 - 1999

Good read here as well

https://www.pajeroclub.co.za/forum/view ... =27&t=1382

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 1:23 pm
by 4ePikanini
Bosbok wrote:Thanks i will replace the thermostat and check if that solves the problem . why do you think someone will remove the thermostat
some mechanics have this ridiculous idea that a cool running engine is a good running engine. Nothing could be farther from the truth. If it is not at operating temp the tolerances are too tight and increase wear - also, the ecu will detect the cool engine and add extra fuel (like a choke on an old carburetted engine) and this hurts your fuel consumption.

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 1:28 pm
by Bosbok
Well it i would say about 10 to 15 min depending on out side temp

Re: 3.5 Water temp drops

Posted: Tue Apr 19, 2011 1:39 pm
by 4ePikanini
Bosbok wrote:Well it i would say about 10 to 15 min depending on out side temp
Jip. that's too long. Definitely replace the thermostat. Take your VIN to mitsubishi and get an original one. Replace the anti freeze while you are at it.