Thermostat on P38, 2.5DSE

Quick bit of advice needed please Guys.
RR just had service at Land Rover agent, not main stealer.
All good but been told no thermostat in cooling system.
I gussed their was not one as on the motorway she does run only in the blue section of gauge.
What are the pro's and cons of having one fitted or not.. Does this affect any engine or fuel performance. I have heard so many stories of people fitting them and the BMW lump over heating.
Been quoted £69.00 to supply and fit as I have heard its a bit of a pig of a job.
Do I really need one fitted??
My RR is a 1998, 2.5 DSE Auto.
Thanks everbody.

Thermostat £10.00 to £15.00. About fourty five mins to an hour to fit. Fit one it is needed for engine to run at maximum efficiency.

Running the engine cold will increase your fuel consumption and is not good for the engine. If you replace it, check that the Viscous fan is working correctly.

Without a stat I was averaging about 22mpg and it was bloody chilly when the bad weather arrived.
Fitted a stat (and a new viscous fan - Xmas present from her) the heater started working properly and on a recent 160 mile motorway trip the dash computer claimed 32mpg. O.K. I don't fully believe the on-board computer but the fuel gauge is definitely not dropping as fast as it did.

be very carefull of cheap thermostats i had a britpart one which cooked my engine when i sent it back and they said it was fine but wouldnt return it to me!
also fitted gen landrover which opened at the wrong temp and caused problems so i then fitted one from my scrap pile which works perfect!
so wherever you get one from test it first before fitting which i had ended up costing me an engine!

i hope for your sake that the thermostat was not removed for a reason!!

I did mine b4 christmas, and as Wammers says, doesn't take so long. nice warm car within 5 mins, and 5 mpg better fuel economy.
a good tip I think is to test your new thermostat before installing: put it in a pan of water and heat it - check that the thermostat opens quickly at the right temperature. And then closes again when you take it out.

Thanks Guys for all your advice, gonna fit one the weekend.

i know im talking to a gost thread here but i also am missing my 'stat. i brought my dse over to spain two years ago and had some overheating issues.. had to take of the aircon belt and i'm looking for my second radiator( if you know anyone, im back in london in may should i leave the thermostat out all the time or put it back in when it cools down... live up in the mountains where it can get cold any time of year... wont to get her working properly but have to think about the climate. not a popular model over here. starting to see why:/

ok - so when I bought mine it had the same issue, under normal running the temp was in the blue, so I thought as many would, that the stat was missing. Turns out it was in there but had just failed? so new stat and runs perfect temp stays around 11 o’clock on the gauge

it really isn’t that hard of a job and if you also carry out Datateks mod to use the A/C fans for cooling, you can do away with the viscous fan and rad cowling giving you even better access to the stat housing

seaninspain said:

i know im talking to a gost thread here but i also am missing my 'stat. i brought my dse over to spain two years ago and had some overheating issues.. had to take of the aircon belt and i'm looking for my second radiator( if you know anyone, im back in london in may should i leave the thermostat out all the time or put it back in when it cools down... live up in the mountains where it can get cold any time of year... wont to get her working properly but have to think about the climate. not a popular model over here. starting to see why:/

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If the cooling system is in good order it should run fine in all temperatures with the stat fitted. I've towed my caravan in 34C and there was no over heating.

I recently replaced the thermostat on my P38a DT, took about an hour and no real problems. I fitted a Quinton Hazell stat, not cheap but has worked fine so far! I didn't drain the whole system as it wasn't long since the coolant was replaced, just under 2 litres of coolant needed to top up (+ water).

fit one.

check its operation before you fit it. Make sure it fully opens.

JohnnyCrash said:

ok - so when I bought mine it had the same issue, under normal running the temp was in the blue, so I thought as many would, that the stat was missing. Turns out it was in there but had just failed? so new stat and runs perfect temp stays around 11 o’clock on the gauge

it really isn’t that hard of a job and if you also carry out Datateks mod to use the A/C fans for cooling, you can do away with the viscous fan and rad cowling giving you even better access to the stat housing

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can you point me as to where datateks mod is i did a search but couldnt find it

mutsnutz said:

can you point me as to where datateks mod is i did a search but couldnt find it

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Sure. PM Keith, it isn't on here as far as i know.

wammers said:

Sure. PM Keith, it isn't on here as far as i know.

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cheers wammers just sent him an email

I had the same with the newer p38 I bought no heating gauge in the blue all the time found no stat fitted so I put one in topped up the coolant and was greeted with the normal hot start issue but with 236000 on the clock I kind of was expecting it to happen, last owner must have removed it to keep the engine cold so it would start

+1 for Datateks mod. Changed my thermostat at the weekend and now running at 11o'clock with quick warm up. Fan and cowling removed leaving loads of space for future work. Did find someone had unplugged the aircon fans, plugged them back in and all working fine. Haven't run it long enough to check fuel improvement as yet.

Lyndasbottom said:

+1 for Datateks mod. Changed my thermostat at the weekend and now running at 11o'clock with quick warm up. Fan and cowling removed leaving loads of space for future work. Did find someone had unplugged the aircon fans, plugged them back in and all working fine. Haven't run it long enough to check fuel improvement as yet.

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if you find any it will be either because your viscous was seized or your fooling yourself

jamesmartin said:

if you find any it will be either because your viscous was seized or your fooling yourself

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In cold weather the quicker warn up makes a small difference and there is a minute overall improvement to fuel consumption. Even when unlocked the viscous consumes quite a bit of power.