Help Diagnosing my Td5 Cooling issue

The thermostat isn't like a regular drop in one thats in the block, its an assembly with inlet/outlet pipes on it that is a part of the coolant hose system. It cant go back in incorrectly as the hoses wouldn't join up.

Just note also, the way it is designed, if the ambient air temp is cold, the thermostat increases the engine temperature by up to 10 degrees to allow for radiating heat from the block etc. It should start to open at 82 degrees and it will be completely open at 96 degrees, but 90% of the flow is hot from the engine and 10% is cold from the radiator. Also at lower revs (<1500rpm) the thermo partly closes and the engine temps will run hotter.

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Originally Posted by Slunnie

The thermostat isn't like a regular drop in one thats in the block, its an assembly with inlet/outlet pipes on it that is a part of the coolant hose system. It cant go back in incorrectly as the hoses wouldn't join up.

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There is a thread on here slunnie, with pics, of the thermostat in backwards, infact, i think there is 2! So it can be done :cool:

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it sounds more & more like the thermostat is shot & stuck closed, forcing coolant through the bypass,

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This sounds exactly like whats heppening, i think the only cooling im getting is from the heater core, which is a worry. Not sure how long its been like this, but im going to assume since I thought I was doing the right thing, and changed the thermostat...

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you cannot blank off the bypass either, as in the 1st diagram

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I can if the thermostat housing has no insides! this will force coolant to flow through the radiator, and it will run cold untill my new PEM101020 GENUINE T-Stat turns up!

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Why not just test it if you are going to remove it anyway?

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I will.

The (my) rave Td5 cooling flow diagram on page 26-1-4 shows the thermostat flow bypass differs to your attachment? Yours makes more sense, so the rave must be wrong?
Regards

RAVE must be wrong cos it shows like the bypass flow comes against the main flow which has no logic

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Originally Posted by sierrafery

RAVE must be wrong cos it shows like the bypass flow comes against the main flow which has no logic

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Rave is wrong.
See my post here
http://www.aulro.com/afvb/discovery-...ml#post2333247

Have you considered that you are trying to fix a problem that does not exist?
I think this is a case of I just got a gauge and I think it runs to hot.
Is it using coolant or down on power?
As Slunnie said and your attachment shows the regulator (thermostat) is not fully open till 96 degrees so you will see that temperature on your gauge.
It does not just open and stay open it will regulate how much coolant flows through the radiator depending on ambient temp and engine load.
If it's plumbed up correctly then its ok. If you want peace of mind get your radiator cleaned out and make sure your fan works correctly.

I believe there is a problem,
I have compared my temp results with others, and the general consensus seems to be a TD5 should operate between 85 and 92 degrees during normal driving.

Also, regardless of how the thermostat in the disco works, the radiator should be WARM to touch, not bounding hot on one side, and ambient temp at the other. No radiator would be THAT efficient.

Sure you're not feeling the intercooler one side? :wasntme:

Sent from my HTC One XL using AULRO mobile app

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Originally Posted by Phat-Customs

I believe there is a problem,
I have compared my temp results with others, and the general consensus seems to be a TD5 should operate between 85 and 92 degrees during normal driving.

Also, regardless of how the thermostat in the disco works, the radiator should be WARM to touch, not bounding hot on one side, and ambient temp at the other. No radiator would be THAT efficient.

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I agree. An if it were me i would be doing a full flush, having the radiator flow checked and at least check the operation of your thermostat in hot water, and replacing thermostat as as just a start.

Problem with these cooling systems is they run with little tolerance, and for peace of mind you need to keep hunting it down until its sorted properly. I had the same with mine (although its a V8) but i spent days trying to sort it all, now i have it runs sweet and im confident it copes under any conditions.

Could be something little like a faulty thermostat, or big like a blocked radiator - at least by eliminating one at a time you will have more confidence in it all once its sorted.

Good luck and keep us posted on your findings.

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.