how hots too hot

[pgrem]

hi all,when i bought my mistral the guy said to ignore the temp guage on the dash as it didnt read properly,it has an aux guage mounted by the radio.the aux guage reads in deg celcius,nothing happens until about 82 when thermostat opens then guage stays around the 80 mark.the guage on the dash reads about 5mill away from the red line.point it up hill and the guage on dash goes into the red and the aux gauge reads about 95.now i want to tow a small caravan and was wondering where the danger point is is it 100\110 ???or what,the system runs50\50 coolant and a 13 pound radiator cap,your help would give me some peice of mind when towing as i get paranoid anywhere near the 100 mark.thanks pete

 

[clivvy]

wel....it doesnt sound right mate.

example, I have a Maverick, so its a TDi engine, where yours will be a TD. No matter what I do, the temp gauge never reaches half way. Up hill, towing, downhill, cold , hot......and im sure many other owners on the club will confirm the same for theirs.

being told to ignore the temp gauge is a bit bad TBH, ok hes fitted an aux gauge, i dont really understand that, but id look into repairing your orginal one if possible-it could very well just be the temp sensor that needs replacing, and I dont think they are very expensive, unless hes re wired it to the aux gauge?

as for towing and allowing temp to rise, there have been soem members on here with this issue, but i believe they ended up fixing it so that the gauge didnt rise so alarmingly...

some more folks with advice will be along shortly im sure of it, Briggie may very well be of some help because hes had a similar issue with his temp gauge before i believe...

 

[harlowmaverick]

it dont sound right at all, check your header tank to see if your getting bubbles being blown in there.
if so it could have engine problems

 

[kbekl]

i had the td and whne i first got it it had a head gasket failiure and that caused my temp to fluctuate after a journey of over 50 miles anything under never showed uo past 1/2 way

after haveing the head gasket done it never rose past 1/4 even spending 3 hrs in traffic going through blackpool illuminations

it depends where the new one is fitted as well because it sounds like it is fitted after the thermostat which would be the radiator pipe work or the radiator its self so would be reading wrong

this was what was happening in my header when the head gasket had gone

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[danielj]

Something wrong there I'd say. Wouldn't think the temp gauge would fluctuate like that. Would have thought it should be as easy to fix the original guage as go to the bother of fitting a new auxiliary one unless there was some other problem involved. How are the water levels in the water resevoir and do you need to keep topping it up? Would it be dodgy water pump? Any idea if there is proper coolant in the system?

 

[pgrem]

hi,water levels remain constant,doesnt use any,has coolant in there im about to do a coolant change though,on the coolant bottle it says that if used 50\50mix it raises the boiling temp to 137 deg.,which is why im confused as to when is it too hot,it doesnt boil but im real uncomfortable driving it just below the red line,it goes to the red line under load,uphill etc but drops to about 82 as soon as load is reduced,or back on the flat or downhill etc.thanks pete

 

[clivvy]

definately not right....could very well be an air lock-coolant not circulating correctly. id get that coolant changed asap, and do the thermostat too, theyre only about £12 ish....

 

[rustic]

I just realised how long this thread is.... Sorry,
Make a cup of tea now, by the time you have read this post it will be ready to pour, if you like strong tea that is .....:lol


Normally the engine is overcooled, the viscous fan keeps the engine cool for ages even before the thermostat opens. (check operation of viscous fan).
The Ram effect helps to cool it. A problem in our winter, I usually place a ply panel behind the top part of the rad, to keep warm in the winter....:naughty


It seems you problem starts as soon as the thermostat should open, passing all the excess heat to the rad.:nenau

1 Check out the thermostat, blocked, broken, test in an "old" saucepan and add water and heat, check temperature' notice at what temperature it starts to open, then temperature when fully open. 80 C to 85 C I would guess.....
Suspend the stat with a piece of wire above the bottom of the pan.

2 You could have a clogged radiator,check the crud in the coolant when you remove the lower hose on the rad.
When changing the coolant, back flush the rad, to remove debris.

None of the above incurrs any major cost, and since you are changing the coolant, virtually nothing. Maybe an hour of your time.


Raising the boiling temperature of the coolant by pressure and antifreeze means that the water in the engine won't turn to steam, for way over the normal operating temperature. So the engine could run into the red line area, BUT you may not know the reason why, no water could be fatal to the engine. But the operation of your engine is not normal. :doh

I have towed 2 tonnes for 4 hours in temperatures of close to 30C in the UK( one of those Hot days a few years back). NOT many hills though, the gauge never moved from less than 50% up.

If you do overheat, open the windows, put the interior heater on full, aim the vents outside through the window. A technique we brits did with 1970's cars, and some still do..:thumbs

Do not open the rad cap when HOT as the pressure stops the water boiling, and if you suddenly release the pressure, it turns the water into "Super heated" Steam.

To check the real temperature, get a hand held electronic thermometer, I have a multimeter with a temperature probe, and check different parts of the water cooled block/ head, radiator etc

Hope this helps, Best regards, Rustic.

Edit: add a bit more....
Temperature senders are not linear, they come in different resistances, so if the wrong sensor is used it might only be right at one temperature, if your lucky.
Like the clock that is stopped it can be right twice a day.... but you don't know when..

 

[kbekl]

when running is the heater working well ?? i mean nice and hot with the blower on full

also when running check their isnt pressure on the top radiator hose once the engine is warm

from what you are saying i would suspect hgf as this was happening to briggie and also me and harlowmaverick also had similar symptoms but his was a cracked head i hope it isnt this and it is just a airlock

 

[lacroupade]

when running is the heater working well ?? i mean nice and hot with the blower on full

also when running check their isnt pressure on the top radiator hose once the engine is warm

from what you are saying i would suspect hgf as this was happening to briggie and also me and harlowmaverick also had similar symptoms but his was a cracked head i hope it isnt this and it is just a airlock

My experience on four of these trucks is that the heating takes a while to get going and lets just say I've driven cars that have had hotter output! But it suffices.

 

[kbekl]

My experience on four of these trucks is that the heating takes a while to get going and lets just say I've driven cars that have had hotter output! But it suffices.

once i had the head gasket done mine was blowing lovely and hot

even blowed warm after the temp rose off the bottom befor the thermostat opened

 

[briggie]

once i had the head gasket done mine was blowing lovely and hot

even blowed warm after the temp rose off the bottom befor the thermostat opened

mine blows lovely and hot after about 5 mins. but the temp guage hardly ever goes above a quarter ... rarely to half way , but soons drops to a quarter

 

[briggie]

in fact , sometimes on the motorway the temp guage drops below a quarter ... hardly registering sometimes

 

[rustic]

once i had the head gasket done mine was blowing lovely and hot

even blowed warm after the temp rose off the bottom before the thermostat opened

I would think that if the head gasket had gone and Gas was escaping, it would collect in the heater pipe thus forming an airlock preventing water flow to the interior heater.

The interior heater is taken directly off the engine block, so it should get warm even hot before the stat opens.

There is a lot of metal, water, oil to warm up before any heat gets through to the cab, then there's that huge damn fan, air cooling the whole lot.
I'm surprised we get any heat at all.

Ok, start, drive a while heat comes through after a couple of miles, but start it up with ice on the screen, and wait for it to melt....... how long have you got.
That's why I'm glad it is garaged.
Right time for the plywood panel for the top half of the rad I guess.

Or take the fan blades off, in the old days a pair of blades could be removed for winter use, remember all the radiator muffs you used to see, aluminium foil etc.
Most cars have electric fans so not as big a problem of over cooling.

Winter draws on...
I said that to the post lady the other day, and she said and 2 pairs of thick tights....:lol:lol

 

[paul7collins]

I have a Terrano mk1 1992 if the top hose is pressured up when running does that mean i have a head gasket gone , i lose a bit of water when running if i put my foot down a bit cannot find any water leaks any where , When it has cooled down i take the rad top of and it needs a bit of water but does not take any out of the header tank

 

[briggie]

I have a Terrano mk1 1992 if the top hose is pressured up when running does that mean i have a head gasket gone , i lose a bit of water when running if i put my foot down a bit cannot find any water leaks any where , When it has cooled down i take the rad top of and it needs a bit of water but does not take any out of the header tank

when running , do you have bubbles in your header tank ? .... large or small ?

 

[paul7collins]

No mate have not noticed any will check thou

 

[briggie]

might help to shine a torch into the header tank to see clearly

 

[briggie]

if you are in sussex ... solarman 216 ( rick ) is your man to fix it if it is a hgf

 

[paul7collins]

Thanks mate i will try the torch trick , Do i just losen the top of the header tank enough to see in leaving the pipe in there,