cooling issues.....again

[uninformed]

Just had my 110 towed home, Im thinking my next work truck should be a tow truck.

Over heating: I headed off for a surf this morning, 5am, 15-20km drive. About 10-15mins into it, and just after pulling over to fill up with fuel, I noticed the gauge sitting on 92c @ 80km/h 4th. This is not normal. Give the time of day, outside temp/humidity, no load on/behind my truck, It would be normal for about 82-85c. So knowing this I watch it closely...sure enough it is rising. Within 1km it has risen to 100c, at which point I imediatly pull over and open the bonnet. Now the reason I didnt shut it down straight away was to keep the system as is and see if there where any pressuised leaks etc. Being still dark, hard to see, but definitely no large amounts of coolant anywhere. I squeeze the main 2 top hoses, and with the engine running at 100c, they are quite soft but hot. . I shut it down and go back to looking over it. After sitting there head in hands, I figure start it up and continue at a slower pace and see how it goes. If it stays hot ill stop and get a tow. I continue on at 60km/h 4th and it is now maintaining 87c. I get to Currumbin and check over it again, now with some more light. No visable leaks but there has been at some point a spray type leak from maybe the expansion tank? (ill come back to this) Top 2 hoses now firmer. I figure go for a surf and come back and check again. 3hrs later I get back and check again. Coolant level is +10mm above fill point in expansion tank. No leaks anywhere to be seen. I pack up and drive off. About 3km down the road is another servo at which point ill so another check. It got upto temp quicker then normal but I figured some residual temp left in block from earlier. Hoses still firm under engine power. I removed the cap of expansion tank and its alot higher ( I figure because its hot) I give the engine a few revs and watch if there are any bubbles, nope but water looks like its moving, and it starts to rise....and out the top. So I stop and replace cap. Had a quick bite (15mins) and headed off again. Within 1km it is getting hotter, the gauge moving quite obviously from 85-93c, then it really starts to move!!! So I imediatlte pulled over and shut if off.

About a week or so ago, I pulled up at home and once I shut off the engine, heard "gurgling" coming from the expansion tank area (from sitting in the cab)...at the time I thought I hadnt heard that before, but figured I was being paranoid about it (had cooling problems over the years) and just to check coolant level etc. Prior to this, I would say the 110 has been operating within 1-2 degrees of normal, but put that down to humidity.

Back ground: For those of you that dont know, the engine is a 2.8tgv (slightly bigger 300tdi), was completely rebuilt 18000km ago. New radiator core, new T/stat. I have the T/stat out to try and check it. It definitely is moving, but I need to source a thermomiter to check at what point it starts to move.

So what does it sound like could be the problem???

cheers
Serg

[goingbush]

Thats a bummer, you didnt get back to the spray pattern neat expansion tank.


As well as thermostat i'd be also be checking the viscous fan coupling ,
any sign white residue (water vapour) underneath the rocker cover oil cap?

do you have a/c worth turning it on to get the condensor fan moving some air & see if that helps.

[Judo]

Sounds a lot like a head gasket to me... Maybe thermostat issue, but the gurgling and rising coolant is what concerns me. When my TDI head gasket went, it was similar. Stopped and revving the engine I couldn't get bubbles to come into the expansion tank, but under load it was clearly over pressurising the system.

Hopefully I'm wrong (I'm not the most qualified here). Will be watching and hoping I'm wrong Serg!

[PAT303]

Pull the thermostat and boil it in water and see if it opens all the way. Pat

[manic]

water pump, loose belt?

88 - 98C are ok temperatures. I thought the cooling system is supposed to be pressurised some what and that overflow from expansion tank is to be expected if you open it after a hot run?

[uninformed]

Thats a bummer, you didnt get back to the spray pattern neat expansion tank.


As well as thermostat i'd be also be checking the viscous fan coupling ,
any sign white residue (water vapour) underneath the rocker cover oil cap?

do you have a/c worth turning it on to get the condensor fan moving some air & see if that helps.

re expansion tank, I thought it may get mentioned that it could have split. Mine was replaced at some point from the black type to the opaque type. The spray pattern to me, looks like it has possibly come from the cap. Im guessing they are set to release at a set pressure and the water comes out the 4 ribs that you grab to do up/undo it. There is eveidence of leaked coolant on a coulpe non-coolant hoses and such near the expansion tank.

No residue under oil cap. Dipstick shows good clean oil.

How do I check viscous fan?

No thermo fan on my truck even though I do have AC. It got removed to fit my winch Long ago.

[goingbush]

How do I check viscous fan?

with engine hot after a run and with bonnet up & engine running, get someone to turn it off while your watching the fan, the fan should stop instantly when the hub stops, if it runs on the fan clutch is stuffed.

actually, something I need to check myself, should all do from time to time.

[LowRanger]

Serg

Seeing that you already have the thermostat out of the vehicle,just make sure that it is fully opening,regardless of the temperature.
Have a good look at the front and rear of the thermo coupling and make sure that there is no sign of any oil,a sure sighn that the coupling is faulty.
Even when cold,the thermo coupling should show some resistance when you try and spin the fan,the resistance should increase,the hotter the temperature. After a drive and at normal operating temperature,get a large paintbrush 4-6" and use the bristle end against the fan blades and see if you can stop the fan from turning,using a normal amount of force.If you can stop it,then the thermo coupling is faulty.Also at normal operating temperature,check that the top and bottom hoses are both hot.

[uninformed]

Pull the thermostat and boil it in water and see if it opens all the way. Pat

attached pics show my test facility (Rick130 patent pending). Unfortunately looks like the T/stat is opening at 82c as stamped and opens a fair way pretty quickly after that.

How far is fully open?

[uninformed]

Pic is a bit hard to see, but Im pretty certain its opening fully(but have never done this or been shown, so could be completely wrong). The "valve" would be moving about 13mm total travel from closed position. I cant see the main spring compressing much more than this??



Wayne, Ill check the fan in the am. I have a feeling it is ok though.