Help Diagnosing my Td5 Cooling issue

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Originally Posted by Phat-Customs

In saying that cap'n jack, tho cooling system must be relatively efficient, if it can effectively cool the engine with only the heater circuit! Which is essentially what's happening in my case.

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Yes i understand what you mean, and i agree, set up correctly these cooling systems should more than cope. Problem is land rover radiators have a history of short lifespans, and when i refer to tolerance i mean they run such high temp thermos, coupled with a completely useless temp gauge in the dash, if something does go wrong, but the time you get a warning it could be all over.

In my system it was running hot, yet at highway speed, it coped so somehow even with a blocked system and a stuffed thermo it still survived.

Just FYI, i came back from a drive no long ago, after you last post i just went out and started by car again - its still hot, and after a few mins running i was feeling the radiator - its even temp all over. Not hotter on one side. Not sure if its different on the TD5 but i would think a rad would be even temp all over not hotter on one side.

With my cooling issue it was a number of things, not just a thermo.

FYI i bought a non gen thermo of roverlord via ebay - was marked 82 deg. My system runs now at 87 all day which is vastly better than with the previous thermo running high 90's

out in the northern south australian heat a couple of weeks ago grumble ran between 160-190F and at times showed about 198F.

at times it sat just over the 190F for a couple of hours.

I'm not sure what the margins compare like in C-F and I tried to calculate it but got stupid results from the conversion formula.

even at a constant 198F there's room for temperature rise without concern so I'm guessing that 96C is probably quite ok , especially if it's constant.

anyone else add to this?

198F = 92.2 deg C

That's a good temp. Low 90's I'd be happy with. At 96/97 degrees during normal driving, it leaves very little room for extra load whilst towing or fully loaded.

I'm ordering a genuine 82* from the UK this week.

Fitted a GENUINE PEL500110.
Cruise temps are about 86*
Idle temps once hot are around 89-90*

Happy chappy.

Tested the BritpArt thermo with boiling water and got a bit of a trickle, compared to the OEM which was a more substantial flow.
Also, the Britpart item, had motorad or similar cast on the side, obviously made by someone else as a generic item.

Attachment 93110Attachment 93111

The last photo shows that there seems to be an ORing or similar dislodged inside, don't remember seeing that in there when I fitted it!

Perhaps it used to work, and at some point has failed closed, or stuck closed etc.

Bit of a trap for young players! Hopefully the OEM one lasts a little longer!

Attachment 93112

This is not the listed thermostat for a TD5, but a cooler 82* variant, I think meant for V8s in the USA and TD4 freelanders.

Will monitor the operation and report back with any positives or negatives.

May you should take a reading with a thermal temp laser gun , at the radiator, at the hose s at the thermostat housing ans at the engine and see what temps they all get. An 82 deg thermostat should open at that temp. what happens after that thermostat could be a different scenario. If an engine is running hot after a thermostat has done its job it could be other issues.

Trip to Newcastle and back yesterday, between 84 and 86* on the madman.
Saw 90* when stationary for some time.
Much better!

My temps seem far more variable than those quoted by others here and I am wondering if my 2004 manual Td5's thermostat needs replacing.

My temperature varies depending on outside temp, how fast I go, how steep the terrain is and how loaded I am.

So, the sort of ranges I get are:
1. Around town, ambient 25 deg, speed around 60 to 80kph, not too much stop start, not too loaded, gives me around 88 to 90deg.

2. Open highway, ambient 25, speed 100kph, flat or gentle hills, not loaded gives me 92-93deg

3. Open highway, ambient 35deg, speed 100kph, flat or gentle hills, loaded, gives me 98 to 100deg

4. Open highway, ambient 37deg, speed 100kph, medium grades, loaded, gives me 103deg

Temp measured with a TM2 sensor on back of block.

Also, around town, whilst the control panel temp gauge reaches normal after about 5 minutes, the TM2 sensor shows it not reaching max operating temp for 15 to 20 minutes.

Should I look at replacing the thermostat?

Short answer , yes replace thermostat
Sounds as if it may be stuck partially closed , hence taking longer than normal to reach operating temp , then restricting flow at operating temp