Thread: Temp Gauge / Overheating problems on a 1996 Defender 300 Tdi

Originally Posted by RDM

G'day all.

.............................. Am I being pedantic or is something still suss?

Thoughts appreciated!

Can't be too pedantic about the cooling system on a 300 Tdi.

Your original problems with an unstable temp gauge reading occasionally jumping to full scale on the gauge was most likely the result of a poor connection somewhere in the temp gauge circuit. This (full scale) is what happens when you have a poor connection with the wire from the sender to the gauge.

Normal thermostat for a 300 Tdi is 88 degrees C. Is this what you replaced the old one with ? and it should be a by-pass type thermostat which is 'different' to your basic thermostat. An incorrect thermostat will cause an over temp problem like what you're having.

Do you have a standard LR setup ? my 1995 Defender 300 Tdi's temp gauge doesn't have a temp scale in degrees just basic C & H markings with a red stripe at the Hot end. Do you have the correct gauge ?

Deano

Originally Posted by RDM

G'day all.

I've had some dramas with my temp gauge for a few weeks now on my 1996 Defender 300 Tdi. Inititially I was cruising along in 5th gear and the temp gauge starting to flicker erratically, including right over to max temp. I pulled over straight away and inspected the engine, with no obvious signs of overheating / coolant loss etc. Too cut a very long story short, I had the radiator checked out and pressure tested, the thermostat and temp sender replaced - however the guage still played up. So, I replaced the gauge and took her for a test run. Nothing unusual initially, and the gauge seems to operate fine. However, pre-all these issues the engine generally sat on 91 degrees (as per the temp gauge), but now it seems to sit on 95/96 degrees - still with no obvious signs of overheating or power loss to the engine. Am I being pedantic or is something still suss?

Thoughts appreciated!

Wild/ quick fluctuations especially UP to hot and down again are usually caused by typical Defender poor body earths. Try an extra earth lead from battery earth terminal to bottom of one seat bolt in seat box.

JC

is there a air bubble in the top of the radiator ? that will be a little problem. i've found filling the radiator from the bung on the radiator as it will fill the expansion tank at the same time and push all the air out at the same time..

Originally Posted by muzza99

is there a air bubble in the top of the radiator ? that will be a little problem. i've found filling the radiator from the bung on the radiator as it will fill the expansion tank at the same time and push all the air out at the same time..

that little hose running from the thermo housing to the expansion bottle via the 3 way valve must be blocked then. it is there to allow any air to bleed off to the bottle.

jc