Isuzu Trooper Owners Club UK™

farflung · Posted: Sat Mar 15, 2008 23:21 Post subject: Temperature gauge

I flushed the radiator on my 2.8td today, renewed the thermostat and radiator cap, refilled with new coolant and tested the system with a longish drive. The temperature gauge barely registered - I mean 2mm .
Does this indicate air in the thermostat housing not allowing the temperature sender to register accurately, some other problem or shouldn't I be worried?

At the end of the test drive the radiator had more of an even temperature than previously when only the top half got hot and the temperature gauge previously showed about a third up from cold when the engine was at operating temperature.

Suggestions and/or advice will be appreciated

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MartQ · Posted: Sun Mar 16, 2008 20:14 Post subject:

Could be a bleeding issue. loosen one of the temp sensors in the 'stat housing and see if coolant comes out.

As an aside, I see you are from Llanbedr, I know it well. I used to be a regular at the Ty Mawr - we used to set up and test mobile tactical airfield radars on the old airfield there until a couple of years ago.
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rallymarshall · Posted: Sun Mar 16, 2008 20:43 Post subject:

the place you pass on the way to shell island Wink

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farflung · Posted: Sun Mar 16, 2008 22:35 Post subject: Reply

Thank you for the suggestion, there is only one sender in the housing so I will crack that one open in the morning. I will post the result tomorrow
Llanbedr airfield I know well. We live on the side of the hill overlooking Pensarn harbour, and the airfield. Until closure a couple of years ago we used to enjoy watching the aircraft and pilotless drones taking off and landing. They also operated a couple of Canberras and a Meteor which were particularly interesting. The airfield is due to reopen in July, mainly for civilian aircraft but I understand that the RAF will have some limited access.
Paul

markymoan · Posted: Mon Mar 17, 2008 1:03 Post subject:

I get worried when mine goes above 1/3, its normal to have low temps on a 2.8 Smile

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:::Matski::: · Posted: Mon Mar 17, 2008 9:31 Post subject:

My 2.8 seized at 1/2 so don't take the gauges word for it.

I don't think the 2.8 runs at low temps I think the gages read wrong.
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farflung · Posted: Mon Mar 17, 2008 17:49 Post subject: Confused

Now I am confused! I cracked open the temperature sender, and I thought that some air escaped.
I hoped that I had solved the problem, but no. Not having time for a long drive I ran the engine at fast idle for an hour, and then drove ten miles. The gauge barely moved, if at all. After getting home
I checked the radiator, hoses etc and they appeared hottish, but not hot! hot!. I would have expected the temperature gauge to climb until the thermostat opened.
Could the new thermostat have opened once, after fitting, and remained open.
I am beginning to wish that I hadn't bothered to flush the radiator as the gauge always read about a third up from cold before.

markymoan · Posted: Mon Mar 17, 2008 17:55 Post subject:

The 2.8 is well known for overcooling, ive run mine without any fan fitted for 18 months, if the cab heater works ok dont worry about it.
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:::Matski::: · Posted: Mon Mar 17, 2008 18:11 Post subject:

Caution I thought mine was over cooling until if seized from over heating at 1/2 way round the gauge. They are well known for over cooling because the gauge says so. But are they actually over cooling?

If the gauge is hardly registering if at all when it did befour then it, the sender or the t-stat are not working properly.

My money is on a duff t-stat.
_________________
Front Aussie Locker - Rear LSD - Petrol Diffs
2" Lift - 1" Body lift - +2" shocks - 32" KL71s
2.5" free flow stainless system - TMIC - 20psi Boost
Suckin' Diesel Baby!

jonkem · Posted: Mon Mar 17, 2008 20:46 Post subject:

I've just had a problem with an "overheating" 2.8 which turned out to be a faulty gauge. The "overheating" had started suddenly and everything else had been checked just as you have been doing.
I'm lucky that I have got a coolant pressure & temperature tester to check the ACTUAL water temperature rather than the in-car gauge.

Obviously check the stat is the right one, 2.8s use a 2 stage stat, and that it does close when cold.
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1994 KZJ70 Cruiser (currently filling the garage and causing some head scratching)
1988 MKI 3.1td Hybrid Van (Ex Bobtail)
1991 SWB Fronty 2.8td Hybrid
2000 Astra Estate (work)
2006 VXR Astra
MK1 SR Nova

markymoan · Posted: Mon Mar 17, 2008 20:51 Post subject:

My stat opens at 82c, dont know about duel stage, mine looks normal with the trickle hole.
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:::Matski::: · Posted: Mon Mar 17, 2008 21:01 Post subject:

jonkem · Posted: Mon Mar 17, 2008 21:06 Post subject:

Most factors will sell you the wrong stat because it is about 1/3 the price of the correct one Wink

_________________
1994 KZJ70 Cruiser (currently filling the garage and causing some head scratching)
1988 MKI 3.1td Hybrid Van (Ex Bobtail)
1991 SWB Fronty 2.8td Hybrid
2000 Astra Estate (work)
2006 VXR Astra
MK1 SR Nova

markymoan · Posted: Mon Mar 17, 2008 21:08 Post subject:

My bad, just looked at my old one, it has a big spring in the middle and a skinny one at the end,, i still dont have a problem, my heater works great and i actually got the temp over half earlier (no fan) revving it at 2500 for 3/4 hour jump starting a paj that has just had a new engine fitted Wink

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farflung · Posted: Wed Mar 19, 2008 19:26 Post subject: A result - I think

I removed the new thermostat, and radiator cap, replacing them with the originals. The temperature gauge rose to about a third up from cold, as before.
I took the new parts back to the suppliers CES only to be told that the parts I had been sold were for a petrol engine. They were very apologetic and delivered the correct parts this afternoon. I have left the original thermostat in situ, but replaced the radiator cap as the original was allowing some coolant to escape.
Thank you all for the help/suggestions