still running hot

[pgrem]

the mistrals still running hot,runs at about 82 deg all daylong unless you point it uphill,then climbs quickly to 100-110degs,point downhill and back to 82.removed thermostat runs at about 60deg,point uphill about 85,pass truck almost 100 again,then back to 60 once on the flat.put our small caravan on the back ran ok for about 40 mins came to a small hill straight to about 110,turned around and came home running at about 80.things ive done,run chemical radiator cleaner through it,backflushed radiator renewed coolant and some radiator hoses,renewed oring and seals under thermostat housing,pump appears to be circulating water well,cant stop fan with a stick(wasnt brave enough to use my hand)ive run out of hair to pull out.ive just noticed there is no lower radiator shroud is this important.its booked in for a leakdown test on tues,any other thoghts cheers pete

 

[kbekl]

loosing any coolant ??

think briggie had a similar problem turned out to be hgf

 

[briggie]

yeah , but hes in new zealand , might be different set up for thermostat there .... check for bubbles in your expansion tank mate :thumb2

 

[briggie]

is the viscous fan working ?

 

[11redrex]

where are you getting the temperature readings from ? I assume the Mistral has a temp gauge of some sort. If so and it shows water temp, what are you worried about ? That's a perfectly normal temperature for coolant to be at.
You didn't say if you'd changed the temp sensor ? Could be faulty but those temperatures really aren't unusually high.

 

[pgrem]

hi,not losing any coolant,have 2 temp guauges the original one which sits about 5 mm below red line at normal operating temp and an in line one which shows deg.somethings up though as it never used to move from either approx 82 or just under red line on dash,now going up the slightist incline temp raisies approx 20 deg or off the original gauge,put the caravan on and even worse.theway it is at the moment cant tow caravan without probably cooking it,cheers pete

 

[rustic]

Hi Pete, I would be checking the temperature of individual points on the engine, with an electronic thermometer.
Front and rear of engine block, top and bottom of the radiator. To check where the cool points are, if the bottom of the rad is cool compared to the top then there could be a circulation problem eg rad blockage or faulty water pump.

If the rad is the same top and bottom, could be the viscous fan.


Just a thought.
Best regards, Richard (Rustic)

 

[solarman216]

I have not found the plastic bit at the bottom of the fan to be worth anything, my guess is the rad is choked up and like CH systems unless the chemicals are really agressive they do not work, and the agressive ones do work but leave your rad full of holes, Rick

 

[pgrem]

the saga continues,took car to radiator shop to get advise\unblocked he took one look at it and said o no not this one again,the previous owners had spent 1700 dollars trying to sort out running hot problem,leakdown tests x2 new custom built xtra heavy duty radiator at 1200 dollars they fitted the xrta guage as they found the original factory one was out,it still ran hot,he said they couldnt get it to boil or leak but it would run up to 120deg,he said they loaded a trailer with approx 1.5 ton and ran it up and down hills and it ran at approx 120deg,he thought they would either get a leak or boil it or seize it,but nothing so he advised them to sell it(lucky me)

 

[makeitfit]

It's been mentioned above but has the viscous fan been checked properly?
Could it be fitted back to front? If thats possible:nenau
Have you got spot lights or other obstructions in the grill, like emus or sheep:lol

 

[pgrem]

hi,i did wonder if the plastic fan could be on backwards?but not sure if this is possible.just has standard bullbar and spotlights,no other obstructions i can see,i keep sheep in the freezer(not like them aussies)lol im hoping the electric fan on the front of the ac radiator is part of the cooling system,it shows it in the manual under radior and cooling as fan and motor but cant find anything else regarding operation.cheers pete

 

[makeitfit]

Air con rad? Is that mounted in front of the cooling rad? If so is it's core clear and the fan working? I guess you need plenty of air to get through the first to cool the second:augie
Sorry I dont have a/c so maybe an expert will advise soon:thumbs
Good luck

 

[Timbo_1975]

Could we have an update on this, as I am quite lost now!

What ambient temps are you experiencing there?

Is the truck loosing water?

Have you got an infra red thermometer you could beg or borrow?

I think you have replaced the thermostat?
Does the viscous fan roar at start up?
Under what conditions does it appear to overheat?
Have you flushed the rad through, and happy the core is not blocked- need that IR thermo really.

 

[lacroupade]

Better still some underbonnet photos would also help....

 

[ssteve]

the rad cowl is very important for the fan to draw the air through the rad and not from anywhere around the back of the rad, even more so in warmer climates with air con in front of rad

ssteve

 

[Timbo_1975]

Agreed the cowl is essential.

This is my set up with 16" & 14" electric fans, which is just sufficient for towing with a 2.5t+ box trailer with quite abit more than standard power.

If the OP's Mistral is an auto, then cooling load will be higher than the manual trans trucks, especially on hills.

 

[rustic]

I would also thought the cowl was essential, and all this hot air has to escape from the engine compartment, so where can it go?

You could remove the lower plastic tray, so the air escapes better, or check that the gaps are big enough for the hot air to escape.

 

[lacroupade]

I left mine off once and temp went bonkers....never again.

 

[makeitfit]

Agreed the cowl is essential.

This is my set up with 16" & 14" electric fans, which is just sufficient for towing with a 2.5t+ box trailer with quite abit more than standard power.

If the OP's Mistral is an auto, then cooling load will be higher than the manual trans trucks, especially on hills.

Timbo, have you had any bother with the through rad fixings ?
I was afraid to do mine that way incase they vibrated a big hole in the rad
Also where did you site the thermo switch thing for them?
Cheers:bow

 

[laurieash]

Have you tryed anti freeze at a 50/50 mix that some times helps to fetch temp down.or more anti freeze than water?