THERMOstat

subusurfer · Post by **subusurfer** » Sat Nov 10, 2007 5:15 pm

im having troubles with my 1991 L series overheating, i think its caused by a stuffed thermostat, i really cant find any other fault possible, but lately it heats up beyond half on a small trip (ie 15minutes) it soon cools down again, if you put it in 4wd it goes off the heat scale. what would i be looking to pay for new thermostat?

ScoobieDoob · Post by **ScoobieDoob** » Wed Nov 14, 2007 11:27 am

i purchased a new thermostay yesterday and the price was $16.95

upon removing the old one i discovered that the thermostat fitted was a 180F unit! explains why it was getting so bloody hot! the correct unit should be 170F, also have you checked to see if your radiator is full of scunge?

discopotato03 · Post by **discopotato03** » Wed Nov 14, 2007 11:57 am

You can remove your radiator and get a rad specialist to give it a flow test , that will tell you if its choked up .

Cheers A .

FROG · Post by **FROG** » Wed Nov 14, 2007 12:16 pm

subusurfer wrote:im having troubles with my 1991 L series overheating, i think its caused by a stuffed thermostat, i really cant find any other fault possible, but lately it heats up beyond half on a small trip (ie 15minutes) it soon cools down again, if you put it in 4wd it goes off the heat scale. what would i be looking to pay for new thermostat?

21200AA121 $37.09 + LITTLE JOHNNYS TEN PERCENT

IT SAYS HERE THEY ARE A TWO STEP THERMOSTAT

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Wed Nov 14, 2007 1:50 pm

Take the thermostat out and see if you can push it open with your fingers, if you can its stuffed. When you get a new one drill a 3mm hole in the outer edge of the thermostat ring, this gives it a permantent decent bleed hole. I would still get your radiator checked as they have a habit of filling up with mud. Lastly if you can pull off the inlet pipe to the water pump and check to see you still have an impeller.

discopotato03 · Post by **discopotato03** » Wed Nov 14, 2007 6:04 pm

Personally I hate the thermostat bleed hole idea unless its like the Triden ones with the jiggler valve . These are designed to stay open if there's air in the system but close against water flow . If they're always open (hole) the engine takes noticably longer to warm up and runs cool in cold climates . A thermostat can't regulate temperature in all conditions unless it can stop the water flow to the radiator if need be .

I like the idea of removing the water pumps inlet pipe to inspect the impeller , I suppose you'd need a new O ring to seal it in again ?

Cheers A .

julian · Post by **julian** » Wed Nov 14, 2007 6:26 pm

If you have a decent thermometer take your thermo out and heat it up in water on the stove. Depending on the unit I think it should start opening around 65-70 degrees celcius and be full open by around 75. Make sure the thermostat is not resting on the bottom of the saucepan, but raised up a bit. If it opens in this range you have a different problem, and you have saved yourself the money not buying a new thermostat.

I am also not a big fan of the self tapped bleed hole, engines are made to run at a certain temperature, not lower and preferably not higher. If you are worried your car is going to overheat then fix the cause before it happens, rather than relying on a 3mm hole to cool your engine. But this is one of those things that everyone has an opinion on.

Subafury · Post by **Subafury** » Wed Nov 14, 2007 9:21 pm

definetely get the radiator checked- i reckon it causes the most cooling related problems.

subusurfer · Post by **subusurfer** » Thu Nov 15, 2007 8:19 am

i finally worked it out, there is a switch i think called a thermo switch which wasn't turning the second fan on, i managed to rewire it, replace the coolant and now it seems to be working fine. cheers for all the advice, i reckon a thermostat probably wouldn't be a bad thing to replace as well.

BENduro · Post by **BENduro** » Thu Nov 15, 2007 8:21 am

I recently changed mine, although I had the opposite problem to you with the temp guage sitting on cold. When I pulled the old one out it was jammed open...Better than being jammed closed I guess;). Replaced it with a Dayco (I think) from Repco, bout $27.
Good luck

YouTube · Post by **El_Freddo** » Thu Nov 15, 2007 12:21 pm

discopotato03 wrote:I like the idea of removing the water pumps inlet pipe to inspect the impeller , I suppose you'd need a new O ring to seal it in again ?

If you're really perdantic about things like that then yes. If not, some high temp silicone around the old O ring does the job - I've done this several times on my L without any problems

Cheers

Bennie