93 Disco overheating issues?

[sickgm]

Greetings,

Just after some advice, my 93 Disco (3.5 V8 on LPG) is having some heating issues.

Around town (60-80kph) the temp gauge sits between just under half and on half. When it come to a stop it drops under half. However on the hwy after about 10-15 minutes it starts to shoot up towards 3/4. A needle width off the 3/4 mark.

I have had the radiator unblocked, thermostat changed, viscous changed and my mechanic assures me it is not a head gasket. There is no coolant leaking or oil and coolant mixing from what I can see.

It does get a fair bit of heat coming in to the cabin around my feet???

Any ideas?

[mike 90 RR]

Greetings,

Just after some advice, my 93 Disco (3.5 V8 on LPG) is having some heating issues.

Around town (60-80kph) the temp gauge sits between just under half and on half. When it come to a stop it drops under half. However on the hwy after about 10-15 minutes it starts to shoot up towards 3/4. A needle width off the 3/4 mark.

I have had the radiator unblocked, thermostat changed, viscous changed and my mechanic assures me it is not a head gasket. There is no coolant leaking or oil and coolant mixing from what I can see.

It does get a fair bit of heat coming in to the cabin around my feet???

Any ideas?

Heat issues are really based on the following

Radiator blocked = heating up
Thermostat = heating up
Blown head gasket = loosing coolant / air bubbles in radiator

Hate to say this but if your not loosing coolant then

Remove thermostat ...... drive it for a while / see what happens .... if running cold then stick in new thermo ..... Also check what degree thermo stat it is ..... Should be 88 degrees??

When you had the radiator unblocked .... You mean the top cap taken off and they "rodded the cores" ..... Did you check via washing the radiator out that the "Radiator joint" actually cleaned out or the cr**p that dropped to the bottom.... Sometimes they forget to do this, and this means all the debris just recycled itself back to the top of the cores ..... Happened to me / Lucky I had checked before installing

Also if you have taken you fresh radiator and then went on a bone shaking drive in the bush then this also could undo all the good work as rust shale is shaken off the side of the block (Steel bore sleaves) and sent to the cores .... Hence blocked radiator AGAIN

Take the radiator and have them check it again ..... And run a "filter sock" (available at all good radiator repair shops) in the top radiator to filter debris before it hits the radiator

Lastly ..... Engine timing ..... Check vacuum advance unit works (suck on hose) and engine is timed properly and mechanical advance weights work properly ..... All easy to check .... very "visual" and cheap to do (free)


But I believe it is in the end ...... the Blocked radiator or wrong / broken thermostat
OR you have a rag / plastic bag stuck IN FRONT of the radiator blocking air flow

Mike


:)

[mike 90 RR]

Just remembered this one Also ..... Check that the hose's are holding pressure ... IF not then replace cap on expansion tank

Phew .... ;)

Mike


:)

[sickgm]

Thanks for the info.

I have had the thermo changed and from my understanding they drilled a heap of wholes in it to help the water flow.

The radiator hopefully has not been clogged again..... as they assure me that they had unblocked it thoroughly.

No plastic bags that I can see......

Thanks, I will keep you posted once it finally works itself out!

[mike 90 RR]

Thanks for the info.

I have had the thermo changed and from my understanding they drilled a heap of wholes in it to help the water flow.

The radiator hopefully has not been clogged again..... as they assure me that they had unblocked it thoroughly.

No plastic bags that I can see......

Thanks, I will keep you posted once it finally works itself out!

Another thought .... You are running gas , which means they have advanced it (the timing)

Advancing can make it run hot (lean fuel mix) .... and check in general, that there is the right amount of gas being supplied to the motor .... IE not running lean

Mike

:)

[ERASER]

I once had a similar problem on a range rover. I did everything youve done. Got the rad rodded, put numerous thermo stats in it, put new viscous couple still had the same problem. Start driving on the freeway and temp would jump to 3/4. I knew something was a miss when i was still able to open the radiator cap while gauge was showing 3/4's. Ended up buying a new temp gauge and sender and problem was fixed. I think from memory it was actually the sender unit that was faulty, but i changed the gauge as well just to be sure. Stayed on 1/4 after that till the day i sold it.

[sickgm]

mmmm very interesting, thats sounds right because after a hwy run i can open the header coolant box and it is not bubbling or anything. Interesting, might try a after market temp gauge? The only heat I get is heat in near my front feet after a long drive.

[sickgm]

Hey Guys,

We have narrowed it down to the sender unit possibly being faulty. After a good drive and the needle going up to 3/4 my mechanic stuck a infared thermometer in the engine bay and had a poke around. Hottest point (except for the exhaust) was 92 degrees which seems pretty normal.

Does anybody know what the standard operating temp is for a disco like this??? (93 V8 3.5lt)

[agrojnr]

My old disco used too sit on 95deg with the aircon on

Change your sender or fit an aftermarket type.

Adam

[cucinadio]

Just remembered this one Also ..... Check that the hose's are holding pressure ... IF not then
replace cap on expansion tankPhew .... ;)

Mike


:)


yes... l did this for the same reason and it really makes a difference...and my vacum advance was stuffed as well so i replaced that and alls well

cheers

[mike 90 RR]

was 92 degrees which seems pretty normal.

Does anybody know what the standard operating temp is for a disco like this??? (93 V8 3.5lt)

Sort of hard to answer .... What degrees is the thermostat rated at that you installed??? .... :confused:

Without knowing that bit of info, You won't know what the difference is between the "Rated degrees of thermo" compared to your measured 92 degrees


RRC EFI is 88 degrees ..... Yours should be the same as you are running the temperature to suit the requirements of the 14CUX computer

IF this IS your installed setup then ......

92 degrees off a 88 degree thermo is a 4 degree difference .... So it doesn't sound that bad ..... But .....The cooling system (radiator) will show it's "health" once summer gets here

If you suspect the sender unit .... Change it .... But keep your eye on it

These motors do not like to be run hot .... I am running a 78 degree thermostat with my 1990 3.9 EFI = temp gauge shows quarter warm ... and I am happy with this setup



question .... Are you running the viscos clutch fan or have you got thermos???


Hopefully someone else will let you know what they measure as a running temp for yours :angel:

Mike

:)

[sickgm]

Yeah my thermostat is a 82 degree one?????? So would 92 degrees be consider to be getting hot?
And I am running a viscous clutch fan.

[mike 90 RR]

Yeah my thermostat is a 82 degree one?????? So would 92 degrees be consider to be getting hot?
And I am running a viscous clutch fan.

Good to here that you kept the viscos as they are always running and pulling air though the radiator & more importantly they are pushing air around the motor when at idle ..... The thermo fans are a good setup but only move air around the engine bay when on (at idle) :)

Sorry ... Still can't give an "informed" answer on "whether it's hot" until the thermostat degrees are known :(

You will get there tho :D

Mike

:)

[sickgm]

yeah I believe that it is a 82 degree thermo. So it opens up at 82 degrees.

[mike 90 RR]

yeah I believe that it is a 82 degree thermo. So it opens up at 82 degrees.

Hi sickgm

I can't actually give you the specs on what the motor should register at operating temp ..... ;)

But :)

A needle at 3 quarter is extreme cause for alarm ... as it is winter and the motor should having a good time for cooling
You have cause for concern & are very correct in attending to this matter ... as the last thing you want is a set of knackered head gaskets

At 82 thermo installed ... I would expect a 5 degree fluctuation .... as the thermostat is to be fully open at the degrees rated .... in your case 82 = fully open

I also had heating issues and it took a while to straighten it out :mad:

All good

Mike

:)

[sickgm]

ok changed the sender unit for the temp gauge and i still have the same problem....... mmm what to do next?

Aftermarket gauge?

[mcrover]

Try fitting a new earth strap from the battery to the engine, sometimes senders can do strange things when they get resistance through the earthing system.

I would check that your system is pressurising as well, as someone posted before, change the cap on the expansion tank or pressurise the tank and make sure there is no leaks that are not dripping but can let pressure escape.

[Discodamo]

I have exactly the same problem in my 3.5 disco... Temp gauge is at half in slow traffic and on the highway it goes up to around 2/3rds to 3 1/4.

It drives me crazy because I need to drive with the heater on in summer to bring it down (usually to around 2 thirds).

Thanks for all the advice guys - I'll let you know if anything works out.