TD4 Thermostat Mod - 83° or 89°. Pros and Cons?

kernowsvenski · Dec 9, 2017

I'm about to embark on the thermostat mod for my TD4 auto. There is a fair bit of info on here about it but I'm wondering about a definitive discussion/summary of the pros and cons of the two different temp options that seem to be most widely used.

Is the 83° or 89° preferred?

Nodge68 · Dec 9, 2017

89°C if you want a hot heater and better MPG.

jedi · Dec 9, 2017

I could do with a hotter heater, but what happens in summer?

dog-man · Dec 9, 2017

You turn the heat down to zero.

Nodge68 · Dec 9, 2017

dog-man said:
You turn the heat down to zero.

This^^^^

pardec · Dec 9, 2017

aircon on

Bonkers · Dec 9, 2017

Is the Renault solution really simply a matter of disconnecting the top hose and stuffing the Renault thermostat into the hose, with the copper bit facing the engine, and replacing the hose.

I ask as my 2005 auto suffers from a lukewarm heater and a needle that does not rise above a third.

I

Nodge68 · Dec 9, 2017

Bonkers said:
Is the Renault solution really simply a matter of disconnecting the top hose and stuffing the Renault thermostat into the hose, with the copper bit facing the engine, and replacing the hose.

I ask as my 2005 auto suffers from a lukewarm heater and a needle that does not rise above a third.
I

Yes. But the auto's top hose is shorter and smaller in ID than the manual box top hose. You can still get the Renault stat in though. It just takes more muscle and lubrication.

The swollen lump in the top hose, is the thermostat inside.

Bonkers · Dec 9, 2017

Thanks Nodge , it seems simple enough just to take off that short length of hose. What’s the tip for easing the thermostat in, heat the hose and apply washing up liquid?

dog-man · Dec 9, 2017

Lots of swearing.

kernowsvenski · Dec 9, 2017

Nodge68 said:
89°C if you want a hot heater and better MPG.

Are there any "cons" to that warmer running?

Alibro · Dec 9, 2017

Bonkers said:
Thanks Nodge , it seems simple enough just to take off that short length of hose. What’s the tip for easing the thermostat in, heat the hose and apply washing up liquid?

A short length of pipe the right diameter so you can push against the casing and not the tip. Also avoid the QH thermostats as their casing isn't as curved so they're harder to push in.

Alibro · Dec 9, 2017

One of these might make it easier.
https://www.ebay.co.uk/itm/Freeland...866227?hash=item4b2c5d6833:g:ulAAAOSwsN9W~9OO

Nodge68 · Dec 9, 2017

kernowsvenski said:
Are there any "cons" to that warmer running?

No. The hotter the engine runs, the more efficient it is. Just don't use a 5w30 oil, use a 10w40 instead.

Nodge68 · Dec 9, 2017

Bonkers said:
Thanks Nodge , it seems simple enough just to take off that short length of hose. What’s the tip for easing the thermostat in, heat the hose and apply washing up liquid?

I find the silicone grease works best as a lubricant to slip the stat into the pipe.

kernowsvenski · Dec 9, 2017

Nodge68 said:
No. The hotter the engine runs, the more efficient it is. Just don't use a 5w30 oil, use a 10w40 instead.

Fair enough. Thanks @Nodge68
My last oil change was not so long ago. I have 5w30 fully synth in atm. Might be worth me waiting for a few miles before doing it then, and combine it with my next oil change..

longdog · Dec 10, 2017

Original thermostat is rated at 88°C.

Bonkers · Dec 10, 2017

Nodge68 said:
I find the silicone grease works best as a lubricant to slip the stat into the pipe.

Thanks once again Nodge, just a final question for you. Looking at the photo of your car it seems the copper spigot of the thermostat is probably half way into the plastic pipe union judging by the bulge location in hose.

I guess as your car is stil driving well that’s no problem?

Nodge68 · Dec 10, 2017

Bonkers said:
Thanks once again Nodge, just a final question for you. Looking at the photo of your car it seems the copper spigot of the thermostat is probably half way into the plastic pipe union judging by the bulge location in hose.

I guess as your car is stil driving well that’s no problem?

I fitted the stat into the hose just far enough so sensing bulb of the stat was in the T piece. This means it can react to the coolant temperature quickly.

Bonkers · Dec 10, 2017

Thanks. I guess it would be difficult to force the thermostat into the hose much more deeply and the more quickly it reacts to temperature the better.

I could have done with the heating working efficiently today but I will have to wait for my thermostat to arrive from eBay.

Thanks again for your guidance.

TD4 Thermostat Mod - 83° or 89°. Pros and Cons?

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