1985 County 110 Izuzu Overheating, Help?

[nic_denmark]

Hi folks.

I have a 1985 County 110 with the 3.9l Izuzu Diesel.

A while back i posted here about it overheating and blowing a hose to the pump housing, it also showed a corroded hole in thermostat housing. both now replaced.
Its alright around town but if i sit on 90km it gets hot....

ive, flushed rad, changed thermostat, changed hoses...

It only gets hot on high speed and around town its fine and sits on half.

Sooo what is it?

These motors have thermo fans? could this be screwed? how do i tell.?

the fan wont move by hand.

Any help muvh appreciated as i currently can leave town in the landy.! :)

Many thanks in advance

nic

[Bearman]

Hi Nic, if it's a standard LR isuzu setup it won't have a viscous fan so not being able to turn the fan by hand will be normal. These motors don't have any history of overheating so there is obviously something causing it. The other thing in the cooling system you haven't mentioned is the water pump itself. If you are satisfied that the the radiator is ok (nothing like grass seeds or insects blocking the core in front or internal blockage in the tubes from corrosion) then the only other suspects are thermostat or water pump. You mention that it blew a hose earlier - was it overheating then? Blowing a bottom hose is usually caused by the thermostat not opening and allowing heat and pressure to build up in the motor. Did you replace it with the correct thermo - should have 82c on it. Are there any other symptoms that led up to it blowing the hose? Other thing I haven't mentioned is the rubber sealing ring that goes on the thermostat - did you replace it with a new one. This is important but won't cause overheating.

[Ancient Mariner]

You will possibly find the initial overheating has disturbed scale which has finished up in the radiator cores:(

AM

[nic_denmark]

Hi guys,

Firstly thanks for replies.

So the leadup to it blowing the hose that links pump to thermo housing. which was very badly perished. I was towing a heavy load and the motor gradually got hot, i was in woop woop so stopped to cool and went again.

It only gets hot under pressure i.e towing or now driving on highway, around town its fine unless you meet a large hill.!

There was a spare thermostat in the landy from pre owner so i boiled that to check it opened and put that in.

Im pretty convinced the rad is ok.... it gets hot on both sides and no core damage... i put the garden hose in top and it flushed through easy.

Another thing is the heater doesnt work!?

Shall i take out the thermostat and take for a drive to see if that changes anything?

Water pump- How to check? i presumed because the system was under pressure and when i ran the motor with the rad hose off it spurted water out that the pump was working.

??????????????

thanks

[Dave_S]

Have you checked to ensure that you don't have an airlock in the cooling system? It may be that your coolant level and flow is lacking as a result.

If you are sure that everything is fine and you don't have an airlock, you may have to remove the water pump to check for internal corrosion or failure. First check the small hole in the pump body behind the pulley to see if coolant is leaking from it.

I have had similar symptoms to yours in the past. Unfortunately it turned out to be the head gasket. :o Given the pain and expense in replacing the head gasket (and the likelihood that it is something simpler and cheaper), I'd suggest you check every other possibility first.

[nic_denmark]

Thanks,#

Yep ive been hopeing its not the head gasket. I have been told that if it was youd see bubbles in expansion tank... which i dont.

Airlock- How else to check? i did think this, when i drained the coolant and refilled i left the nut on top of thermostat off and cap of tank and left it for ages.. however i think the heater matrix has a fault as only one pipe is hot going into it... could this be the fault? and so no hot air inside vehicle.

I guess i could go get a compression test done to see.... ugh.

ill check water pump hole later and if i need to i guess ill take it off and see if it ****ed.

Do these not have thermo fans??? i was reading up about the different fans etc.

Why is it that if i turn off highway and its nearing the red that within 30sec the temp drops right down,.,

thanks everyone for help/advice. please keep it coming.

[nic_denmark]

any more advise???

[Phil B]

Nic,

The standard 4BD1 does not have a viscous coupling on the fan but it is a common modification. Does yours have one? If it does it may not be working. They only work when the engine starts to heat up under load. You should be able to hear it come in.
Dont run it without the thermostat and check that it actually opening at the correct temperature (should be 82deg).
Have you checked that the motor is actually overheating? A test is run the engine hard up a steep hill under load. When you see the overheating starting pull over and switch off. Immediately check the actual temperature around the sender on the block with an infra red temperature reader (cheap at Jaycar or Dick Smith).
If the temp is under 100deg it is not overheating and then suspect the sender unit or temp guage.
If all of this fails take the rad into a specialist and have them rod the core.
Also take the pump off and check for a worn or blocked impellor.
Regards,

[Bearman]

any more advise???

What have you checked Nic, Did you find anything?

[nic_denmark]

Phil and Bearman cheers

im going to do those tests you just wrote and check the water pump also.

I shall report back.

Thank you

[nic_denmark]

Morning guys.

So through process of illumination ive got to the heater matrix and bypassed the pipe and isolated it... took for a drive down roads and up the hills it used to get hot on and it was fine!!!!
So is the heater matrix blocked and producing air pockets?
Im going to take it off and apart today but can drive it at least now.

Anyone have a problem with the heater pipes, system?


Also on topic of county- What oil for diffs? and gear box? thought id change oil while im at it.

Much appreciated help by you all.

[Bearman]

Morning guys.

So through process of illumination ive got to the heater matrix and bypassed the pipe and isolated it... took for a drive down roads and up the hills it used to get hot on and it was fine!!!!
So is the heater matrix blocked and producing air pockets?
Im going to take it off and apart today but can drive it at least now.

Anyone have a problem with the heater pipes, system?


Also on topic of county- What oil for diffs? and gear box? thought id change oil while im at it.

Much appreciated help by you all.


Hi Nic, can't say I have seen that one before but it is possible I guess. What gearbox does yours have - 4 or 5 speed. The 4 speed requires a light oil 15w40 or 20w50 engine oil in both gearbox and transfer - use the same oil from engine to transfer. For the 5 speed 20w50 or Castrol syntrans and 80w90 or VMX80 in the transfer. For the diffs 80/90 gear oil.

[flagg]

Hi Nic,

The problem might be that the heater is higher than the bleeding bolt on the thermostat.. Mine certainly is. I got around it my making a "T" and installing a bleed valve on it as per the picture below:

http://www.aulro.com/afvb/attachments/members-rides/65901d1379755385-hercules-isuzu-110-wp_20130921_006.jpg

If I was to do it again I would just have a bolt and not a valve as the valve leaks a bit and it would be just as easy to loosen off the bolt and wait for the bubbles to stop as it is to press on the valve.

Basically after I've flushed the coolant and bled it once normally I go for a drive with the heater on and stop periodically and tap the valve to see if any bubbles come out. Almost always there are some.

This has the added benefit of making sure your heating is working as well as it can (which was my primary reason to do it - Canberra gets cold!).

[nic_denmark]

Thats a great idea.

I took off the heater matrix and put the garden hose on one end... it flushed out brown for nearly 5 solid minutes...!!!! made a right mess lol.

I then reinstalled it and put new hoses on, i only had time to take for a short run but my heater was 'warm' and it didnt over heat... so im on to it.
Last thing i thought of and last thing i checked was the fault to be the heater matrix, im surprized more people dont have this problem seeing its higher than the expension tank.
But fingers crossed its now on road to recovery, i may however take your advise and install a bleeder to drain any air up that way.

Do you know on top of the matrix what the pull cable does, i know the one on the side closes off the heat flow but the top? (its not a major thing to know for me)

Im chuffed i fixed it without a major bill from a real mechanic.

Thanks all for help and thoughts.!

[JDNSW]

One of the controls switches the air intake from through the matrix to bypass so you get air in that is only heated by the exhaust in summer. The other one swaps between demister and feet. The third one, which also has the fan switch, adjusts the air quantity, but I can't remember which is which! (This is on the non-factory air)

John

[Phil B]

Hi,
The cable on the LH side of the heater matrix box is the air on/off control which is linked to the blower fan lever on the left of the dash. The cable on the top is hot/cold air which is linked to the temp control lever on the right of the dash. The demist/feet lever (on the right of the dash) is linked via a cable to the air box behind the dash board.
Regards,