Odd heating of engine

[danielj]

Anyone any ideas what might be causing needle on temperature gauge to run unusually high. Temperature gauge normally reads just a shade under halfway and does not move from that once warmed up no matter how far or fast I'm driving. This morning after about 50 miles driving the temp gauge went up to about three quarters and stayed there for a number of miles before I reached my destination. Water level in resevoir was a bit low but was not empty. I added about a quarter litre of coolant to the resevoir and ran the engine again and the needle went back up to three quarters and stayed there while the engine was running for about 10 mins.
There has been no sign of a water leak since I changed the water pump a few months back. It does use water though and the resevoir bottle needs to be filled again every 5 or 6 hundred miles.
Any ideas.

 

[clivvy]

eyup. i am no mechanic, but if its using coolant/water then there must be a leak, air bubble or something more serious (I dont want to go down head gasket route). Have you tried changing the coolant again, and running engine with rad cap off till it bubbles? Hows the thermostat, is that opening correctly? Just seems to me that if you are filling it so often, then something isnt circulating correctly perhaps...

first job, check the pipes. Then I would check for air bubbles etc, could be that coolant isnt circulating correctly...

 

[extreme-4x4]

thermostat stuck that ll cause it to blow out the top of res tank

or casket on the pump not sealed

 

[jonno]

have you checked the oil. if its low it will cause the engine to overheat.if theres a brownish creamy whitish gunk in the oil filler cap then the headgaskets gone and thats where your waters going(into the oil).
thats all i can think of but i'm sure someone with more know how will post soon

 

[danielj]

Thaks all for replies.

It may be thermostat stuck. Tried to change it when changed the water pump a few months ago but one of bolts on engine was seized so couldnt get at thermostat and decided to leave it alone as it did seem to be working fine at the time. Odd though that the thermostat usually works fine except for this morning after about 50 miles. Maybe I need to have a go at it again.

A leak would seem the obvious problem for the use of water although I haven't seen anything. But a leak wouldn't seem to have anything to do with my heat levels rising this morning as there was some water in the resevoir and rad was full. I did try opening the rad and water did bubble out.
Almost certainly not a leak at the gasket as I have kept an eye on this since changing the pump.

The oil should be full up and has been recently changed. There was no sign of water in the oil when changed or or any gunk or other signs of water getting into the oil.

 

[elty001]

sounds like mine and that was a sticky thermostat,which i still havn't got round to changing.
gonna do it when i'm off work over crimbo.

 

[lacroupade]

Does sound like the stat Dan...had the same problem, and of course its cold enough at the moment for it not to overheat completely.

Stat housing should just be three bolts? Try soaking them with WD40 overnight and see how they come off.

A while ago I bought a set of really useful sockets that are meant for getting out bolts or nuts that have rounded, they have a knd f reverse thread inside them that grips the bolt/nut as you rotate it - you might need to same thing if your spanners fail you!

One thing to watch with these as well; sometimes the rad cap fails and leaks quietly under the bonnet until a lot of the water has gone from the rad, yet its possible for there still to be water in the expansion bottle under such conditions (making it look as if everthing is OK) because the cap has lost the ability to suck it back into the rad when it needs it.

 

[tezzer]

if the bolts are siezed that hold the thermostat housing, after soaking with wd40, try heating the casing with a blow lamp, aluminium expands quicker than steel and should loosen the grip on the bolts. :thumb2

 

[danielj]

Thanks for all the replies. It does sound something like the thermostat. And as mentioned it may just be too cold for it to overheat completely. Will have a go at the WD40 and will look out for some of those special socket things. Sounds useful. Heating the casing first soundls like a good idea. Will have a go at it over the christmas hols.

 

[danielj]

Changed thermostat today. Thanks for advice on WD40 and heating to loosen the retainer bolts. Bolts came loose very easily. The workshop download on changing the thermostat was also helpful. Took the T2 for a short drive and ran the engine for about 30 mins and so far so good. Its a bit early to tell whether problem is solved yet though as it was generally heating up after about an hour's driving. Anyone know if it is unusual for there to be no gasket, and no sign of liquid gasket either, on the thermostat casing. Was no sign of any on mine and the paper gasket that came with the new stat bore no relation to the shape of the casing. Put things back together as I found them with no gasket. There is no sign of a leak so far but should it have a gasket?

 

[jims-terrano]

Yes there should be a gasket, the gasket that came with my stat didn't fit either so I used instant gasket on top of the old gasket.

Jim T

 

[danielj]

Yes there should be a gasket, the gasket that came with my stat didn't fit either so I used instant gasket on top of the old gasket.

Jim T

Thanks, looks like I will have to do some pasting.

 

[danielj]

Odd heating of engine seems to be solved since changed the thermostat. Temp gauge reading steady just below half way no fluctuations. So looks good. Thanks all for advice.

 

[jims-terrano]

Just out of interest did you fit an 82 or 88 degree stat? and has it made any difference to the heater.

Jim T

 

[lacroupade]

Odd heating of engine seems to be solved since changed the thermostat. Temp gauge reading steady just below half way no fluctuations. So looks good. Thanks all for advice.

The T2 can be a niggly old cow sometimes but its fundamentally pretty bomb-proof - its pretty rare for anything really bad to go wrong, usually just takes a bit of elbow grease and consulting with the lads!

Nice one Dan.:thumb2