Club 80-90 Forums

I've just had a recon engine and head fitted and am going through the running in stage but the temperature is a little hotter that normal, it used to always sit directly over the led in the middle now it is past that about 3/4 of the way to max. but I drove for about 100 miles today and it didn't increase. just in case, I left the heater on max for the trip and this stayed constantly hot so I guess no air locks?, the coolant is full in the expansion tank and the top up tank is also full. I haven't checked the fan yet but wouldn't have expected this to kick in under normal conditions. Im using mineral oil for the run in, would that cause the engine to run slightly hotter?

What I would do in a similar situation:

1. Call the reconditioners and explain the increased display on the gauge. They may have an answer for you
2. Watch that gauge like a hawk.
3. Drive with the heater off....if the engine fails you want it to fail under warranty


You can install a thermostat that opens sooner...but again...get permission from the reconditioner first!

Sounds like you are doing all the right things, though.
oh - what you could do is whip the grill off after a drive and make sure the rad is uniformly hot, and there is no air trapped in there - just cos the heater is constantly warm does not mean the rad isn't half full of air! (and they can be a pain to bleed)

Em
x

All the gauge is _actually_ telling you is what electrical resistance it's seeing from the sender in the thermostat housing. A different sender may well give a different resistance for the same temperature. So a different position on the gauge isn't actually telling you very much at all. It's what the needle DOES that tells you everything.

If it's starting off at cold, rising quite quickly, then sitting pretty much level no matter what - that says the thermostat is working. If it only rises a little in extreme provocation, then the fan kicks in, then the fan and rad are working.

You don't want the engine running too cool, any more than you want it running too hot. If you're really worried, get an IR thermometer (less than a tenner from the 'bay), and see what temperature you're getting at various places. You should have about the 'stat opening temp at the 'stat housing, once it's properly warm. You should see that drop a bit along the length of the pipe to the rad, drop a lot at the rad, then drop a bit more along the length of the return pipe. Various bits of engine metal may well be a lot hotter.

Thanks for the info both good advice. Was going to do another air bleed and check the fan. I can borrow a IR thermometer from work so can try that. I presume the fan kicks in at a pre determined temp so if I first check the fan. I saw thread for that somewhere. If it doesn't kick in its not as hot as what the gauge is indicating can I check aprox temp with the IR thermometer. Where is that sensor located could it have been damaged when the engine last got overcooked? Is it a cheap thing to replace?

I'd be inclined to flush out the coolant system..take off and clean out any small bore coolant pipes.
I had a recon engine fitted couple of years ago and found some of the pipes completely blocked with crap..
The suppliers had bead blasted the engine but not flushed it out fully (if at all)
Also replace thermostat with new one.

I have rebuilt many engines and it is reasonably common for them to run a wee bit hotter with all the new compression they never had before. My present DG infact with the same stat and sender but new piston rings and bearings increased the gauge from on the led to just to it's right. My old LDV with a perkins prima diesel also increased from 1/4 where it always sat up to half way after reconditioning.

Just another thought if the dalek cap is broken and it doesnt open to release the coolant could that cause it to run hotter. As in effect its now a closed loop under higher pressure so higher temp. I only say this as I haven't seen any increase in fluid in the tank behind the number plate, or decrease as it cools down but did see the level drop slightly in the top up tank with the dalek cap also the connecting pipe isnt very tight so might let a bit of air in rather than sucking the water in?

A failed cap wouldn't make it run hotter, just make it more likely to pop a hose. Your 1st port of call really needs to be the installer.

Also just noticed you mention the last engine got cooked..... Did you find the reason behind that?

On the last engine it sprung a leak on a coolant pipe I pulled over topped it up drove a couple more miles ran out of water so called the AA he found a leaky pipe but couldn't fix it so topped me up and gave me spare water for the 10 mile trip home I pulled over 3 more times but on the last bit I pushed it to far. I repaired the pipe fitted new rad new thermostat and water pump but noticed bit of oil in the water drove a few miles down the road and the temp crept up , pulled over retopped up but when I went to restart plumes of white smoke came out. The head was cracked and warped and there was signs of damage on the block so replaced the lot as well as a new thermostat. Im going to call the supplier to double check.

Did you change the stat after the cooking in a camper incident?

Yes changed the stat but havnt checked the temp sender yet either