ENGINE TEMPERATURE RUNS HIGH

[DublinChris]

Hi been off forum for a while putting up the miles on my 1998 Series 2 turbo diesel - just turned 170,000 miles. I have a question about the engine temperature during our recent hot summer. While out on open road the temp is fine but as soon as I hit traffic and driving around town the gauge rises and continually in slow traffic rises to the point where the fans cut in. Up to this year I had not noticed the fans cutting in soo much but this year its every time i slow down in traffic. Is this normal or could there be something going on in cooling system maybe due to age? There are no leaks and coolant level is fine
Should add that rad was replaced in Feb 2011 with one from GSF

[Mandrake]

If they come on more than you remember it could be the thermostat not fully opening and therefore needing replacing, however its fairly normal on any car for the radiator fans to come on for a couple of minutes shortly after going from fast cruising to being stuck in stop start traffic as there is a lot of latent heat built up in the engine but the cooling effect of the wind on the radiator is suddenly removed.

As long as the temperature starts dropping again when the fans come on and doesn't exceed the point where they kick in, and it doesn't overheat under load up a hill at speed its probably nothing to worry about.

It wouldn't hurt to replace the thermostat just to be sure though.

[DublinChris]

Hi Mandrake
I suppose having had the car since 1998 it was a sense that they seemed to be coming on more than they would have done in previous years. When they cut in the temp does drop back ok but if continuing in heavy traffic the temp will rise quickly enough again and fans come back in. Once away from slow traffic and some fresh air blowing through the temp goes back to normal. It just seemed that temp rose and fans cut in a bit more frequently this year. Up hills etc is not a problem just peak traffic. Was concerned that there might be some blade wear or similar in pump.

[Mandrake]

Unlikely to be a problem with the blades of the pump I would have thought. When was the last time you changed the thermostat ?

If it was more than 4-5 years ago I would change it anyway. Which engine do you have exactly ? I'm sure someone can tell you where the thermostat is and how easy or difficult it is to get at if we know the engine. (I'm not familiar with the diesels myself)

I'm also assuming that regular coolant changes have been done over the years so that there is unlikely to be a build up of scale in the radiator and hoses ?

[DublinChris]

When was the last time you changed the thermostat ? Errr...I have had the car since 1998 and I am scratching my brain but cannot remember if it was ever changed in those 15 years - so possibly never

Which engine do you have exactly ? 1905 turbo diesel car is a series 2

I'm also assuming that regular coolant changes have been done over the years so that there is unlikely to be a build up of scale in the radiator and hoses ? I replaced the radiator in Jan 2011 and apart from odd top up coolant has not been changed since then. I did spring a leak earlier this year when the thermostat housing developed a tiny crack and sent out fine spray of coolant onto engine block when under pressure. Housing was changed and some coolant added but thats about it

[oscar]

hi if not had "good" anti freeze in or plain water for periods you can get wear on pump impeller from dirty water if an aluminium impeller which are the best anyway as most steel ones are pattern parts and many cavitate (whip up air like a boat propeller) good way to check flow is with it warm look in header tank you should see it turning the water over also on top behind diesel pump theres a schreader valve well cap anyway on small water pipe which is return from head its for bleeding system ondo it you should get a decent spurt of flow coming up give it a little rev and should increase output then while holding revs rescrew cap so not letting air get back.
so if that works pumps ok
some after market rads arn't great and it don't hurt to change thermostat anyway but keep old as spare in a plastic bag as not unknown for new one to fail.
also check fans are running at half speed as that might not be working so notice when on full speed as noisey low speed will be on longer to cool than full so more a gentle flow so if not working gets hot misses that then has to go full which drops it alot then repeats

[DublinChris]

Thanks for that Oscar will check flow. Coolant would be of good quality and no plain water used.

[Hell Razor5543]

There are different types/colours of coolant, and you should use the right one for your car. One way to find out what type you need would be to go onto Euro Car Parts website, enter your vehicle reg, and then search for coolant.

[DublinChris]

There are different types/colours of coolant, and you should use the right one for your car. One way to find out what type you need would be to go onto Euro Car Parts website, enter your vehicle reg, and then search for coolant.

Checked the site and basically it gives option of both red and blue. I am currently using blue.

the vehicle reg did not work as I am in Dublin but I was able to put in vehicle type etc.