Nope not the JTD, but my girlfriend's Mk1 55 SX.

Driving it to work this morning and noticed that the interior fan was blowing cold air even though the engine was warming up. About 5 miles into my journey the engine started to continue heating up past the halfway mark. It got to around 3/4 of the way up and stayed there and then fluctuated between 3/4 and halfway for the rest of the journey.

I also noticed that the engine fan wasn't cutting in, but there isn't any smoke/steam from the exhaust and when I felt the coolant bottle/pipes they didn't seem overly hot. I was in a rush so couldn't check under caps/levels etc but will go up at lunch and take a look.

So what are we thinking? Coolant low? Fan broken? Air lock? Not really thinking HG right now as it stayed at 3/4, there's no white smoke from the exhaust and the engine is running fine...

Cheers in advance

Mark

ok so a bit more information for you...

Typical bloody woman Oil at the bottom of dipstick indicator, coolant about 3 inches below min until i took the cap off and then it came up to about 1/2 inch below min.

There's a tiny amount of mayo in the cap but i'm putting it down to how it only ever gets used for her 10 mile pootle to work and back and hasn't been driven since christmas eve.

so topped up the oil, going to top up the coolant before i leave for home and if it's still overheating then i'll bleed it as it's likely there will be air in the system

i'm guessing (from reading other threads) that low coolant can contribute to the fan not kicking in? but will check that when i get home as i've got nothing with me to help...

I've heard of low coolant affecting the fan not kicking in, but I would be inclined to check the thermostat to make sure there is a flow of hot coolant to the radiator and you havent got a system lock there or anything that daft.

Having said that, was the temperature fluctuation seemingly associated with he vehicles velocity or irratic? When I was having heating trouble in the summer the gauge would sit at half way most of the time, creep up to 3/4 and the fan would kick in and blow it down to 1/2 again (tested whilst stationary with the bonnet up to confirm)

If your feeling brave you can test the thermostat without taking it off by having the cap off the radiator and warming the engine up and watching for a bubbling action. This however may not be the thermostat and be airlocks working out and I wouldn't recommend it unless you cant get the thermostat off (and be careful using that method, they can spit hot fluid!)

5abr3 said:

I've heard of low coolant affecting the fan not kicking in, but I would be inclined to check the thermostat to make sure there is a flow of hot coolant to the radiator and you havent got a system lock there or anything that daft.

Having said that, was the temperature fluctuation seemingly associated with he vehicles velocity or irratic? When I was having heating trouble in the summer the gauge would sit at half way most of the time, creep up to 3/4 and the fan would kick in and blow it down to 1/2 again (tested whilst stationary with the bonnet up to confirm)

If your feeling brave you can test the thermostat without taking it off by having the cap off the radiator and warming the engine up and watching for a bubbling action. This however may not be the thermostat and be airlocks working out and I wouldn't recommend it unless you cant get the thermostat off (and be careful using that method, they can spit hot fluid!)

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Yes! When i went round a right hand bend it would raise quite quickly and would just randomly cool down quickly again while driving along. i assume thats because the small amount of coolant was being sloshed away from the pick up point?

Yes I would imagine thats down to the amount of fluid in the radiator, or at least where the hotter section of fluid is and it getting closer to the pickup as you go around the bend, looks like its time to check the radiator for an airlock for certain!

Topped up the coolant and all is well now

Keep your eye out for leaks now

5abr3 said:

Keep your eye out for leaks now

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Meh she's getting a new car in the next few weeks so just keep topping it up if need be