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Diesel top rad hose - Inline Thermostat housing

44K views 138 replies 33 participants last post by  COLVERT 
#1 · (Edited)
I am experimenting with an in line thermostat housing so needed a top hose as a standby. It seems to be listed as 'no longer available' but I have just picked up a brand new one from Whitehouse Rover MG on
01322 559180 complete with all fittings and hose clamps for £19.39.
Worth trying them for any parts which you find hard to locate.
 
#94 ·
I posted a comment about the 'push-in' type thermostat some time ago ( when it was freezing cold, remember?) The one I used was intended for a Renault, but only had an opening temperature of 83 deg. This at least was a very cheap and simple job, and is invisible. At least the gauge now sits at 'quarter to' although the real temperature is, of course, not as high as it might be.
I've read posts that expressed some concern about how such mods might behave in the hotter weather. Well, I've just returned from a holiday in France where we were driving around in air temps of 31 deg. up hill and down dale, and the temp. remained steady. So I'd say say this is mod well worth doing; I'm now on the lookout for a 'stat with a higher opening temp!
 
#95 ·
I've read posts that expressed some concern about how such mods might behave in the hotter weather. Well, I've just returned from a holiday in France where we were driving around in air temps of 31 deg. up hill and down dale, and the temp. remained steady. So I'd say say this is mod well worth doing;
I'd agree. Albeit lower temps here obviously, but I don't think the engine warms up very much faster than it did when we had the below freezing weeks and I have not seen it running any hotter than it did then either.

The doom-mongers have been proved wrong. I'm not surprised.
 
#97 ·
I fitted a thermostat for a Renault 5 into the top hose the other day. It's a standard 88º as I forgot to ask them to order a hotter one so not ideal but,

After a couple of good long high speed runs on reasonably warm days I can report:

The gauge now goes up to exactly the halfway mark and stays there. Before it didn't reach a quarter.

Using the on board thingymajig the temp varies between 87ºc and 91ºc, the highest recorded being a mere 94ºc when climbing a bank on a dual carriageway at high speed (75 CDT Auto Tourer).

Still not as hot as it should be, but a LOT better than it was with no sign of overheating whatsoever.
 
#100 ·
I would have thought a 92º stat would be available to order.
I had to grind round the outside a touch to reduce diameter, be careful not to cut through. Used some lube and it pushed in with a struggle.

As for the MPG, Yes it's a lot better, BUT I also cleaned the MAF, the EGR and changed all filters at the same time so obviously I couldn't say what has made the difference.
 
#104 ·
A quick update to my Renault 5 stat fitment.

I returned home last night from an 8-day 1,046 miles trip to Europe.
The car behaved impeccably throughout. MPG much, much improved, although I did carry out a service and replaced an injector in addition so the gains will be due to a combination of factors. I do believe the stat has played a major part though.

On screen MPG was 52mpg at one point. That's at least 11mpg higher than ever seen before!

When I filled up the display was 40mpg, when calculated it was actually 44mpg. That's a Conn Tourer auto with 4 adults and back full of luggage, touring narrow country lanes for much of the time.

I'm happy with that.
 
#107 · (Edited)
As regular followers of this and similar threads will know, I'm a bit of a lone voice regarding the need to get diesels hot. I bandy 95-105°C around as optimal, but many here would scream 'overheat' if it happened to their engine and pull over for a bit.
Anyway as you may know, here's a similar thread running on the other channel and I'm on my own there too (temperature wise). So, I was pleased to read a new contibutor to the diesel temperature debate and I'm sure he won't mind me quoting his first post to that particular thread.

Karlglund's post:
This is one subject I know very well is diesel engines...

For a diesel engine to get its best peak proformance it has to run as hot as it can without overheating the engine coolant..that is why you have to make sure your coolant is mixed correctly half and half exactly..

- - - living in Canada all trucks and cars with diesel engines we would change the thermostat twice a year one for summer and one for winter..a higher degree thermo. for winter and 10 to 20 degrees lower for summer...we never use specs for the truck or car - - -

You want that engine to run as hot as possible...this way you get the best preformance from it.

I talk to my father for we own diesel trucks and have several diesel cars back home he said best is 203 degree or higher fahrenhite..thermostat for a diesel engine to get the best fuel milage and preformance.

In Canada our winters can go as low as minus 40 to 45 without wind chill so running an oem spec thermostat for any diesel would not make the cut...we run our deisels engines so hot that we do cook on them.. and no it does not hurt the engine..

(Unquote)

203°F = 95°C

I've read US and Canadian trucker forums and it is clear that high temperature give better fuel consumption and general engine efficiency. These guys need every yard they can get from a gallon. It's also bourne out by the physics, but that's a harder hill on which to push the story.

Simplistically: Engine hardware hot as pos. - Inlet air cold as pos.
I also know some truckers run neat propylene glycol as coolant in a sealed system. That will go way above standard EG/water mix.

TC
 
#111 · (Edited)
Can't argue with the logic, but in practise in the depths of winter I'd sooner keep meself warm and the windscreen defrosted than worry about the engine being a tad chilly! :)

Having read of all the problems with the diesel thermostats I've been expecting mine to give up but it is in its eleventh year and still doesn't appear to work any different from when new.

Mike
 
#113 ·
guys hello there, i found this thread via google, i was searching inline thermostat housing. I have an audi a4 2.5 tdi v6 quattro sport. Anyhow the thermostat is faulty, my temps are low and so is the heater air is only mildly warm. To change the thermostat on this engine it requires the front off the car and a full timing belt removal just to change the thermostat which is a huge expensive job on this v6. I sounds bizzare but i have had a couple of audi mechanice tell me this on the audi forum so its sound information.

anyway this is interesting, i had a brainwave of fitting an inline thermostat housing and i stubled upon this thread. so is this CHEVY INLINE THERMOSTAT HOUSING the best you have found to use? Is there nothing in the uk. I found this on ebay clicky could it be adapted ??

cheers
rab
 
#114 ·
anyway this is interesting, i had a brainwave of fitting an inline thermostat housing and i stubled upon this thread. so is this CHEVY INLINE THERMOSTAT HOUSING the best you have found to use? Is there nothing in the uk. I found this on ebay clicky could it be adapted ??
You are on your own here as a Rover/BMW engine is not the same as what you have and I know I am not qualified to give you any particular advice as to if it'll work - but you'll need to know the internal diameter of your hose to be sure to get something to fit (I'd grab an old one of a scrap car to cut and measure).

Then look at the various internal thermostats that are now being used on Rovers as if you can find one the right size for your hose you are laughing as they are only a tenner or so. But I have found the Mezere housing to be an ideal solution for my problem albeit somewhat more expensive!
 
#117 ·
In line thermostat

cheers for the reply matey, i can easily pop off the hose and measure the diameter with calipers, ie the outlet pipe outer dia. whether it will fit those rover ones on ebay i dont know but i can maybe adapt them to fit if there is a slight difference in size. i just think it might look pants so the Mezere ones might look more oem for when i sell the car. I still need to feel the hoses warming up to find out which one heats up first so i know thats the feed in.



The Mezere one looks much better i agree and it looks well made, i may just bite the bullet and go for it, i just thought id see if there was any cheaper options first. Ill also need to check what the temp rating is on the audi thermostat.
I read somewhere folk had bolted 2 thermostat housings together to make a make-shift inline housing, quite a good idea but it would look shíte lol.
My local 1 man garage done my in line thermostat last friday,he removed the top hose took it to his workbench,with the help of hot water and liquid soap the Renault 4 thermostat just slid into the hose,Car now runs at normal temperature...........Tom
 
#115 · (Edited)
meziere HOUSING

MYSTIC BERTIE: I am the person who fitted the Meziere thermostat housing over 14 months ago and I have had no problems since. If a housing could be fitted in the
top hose of your car you would need to ascertain which size inlet and outlet
you needed and Meziere would happily supply what you require (the Rover top hose is tapered so requires different inlet and outlets). Their housing is a quality item which accepts any standard diameter thermostat (2.125"). It works out as somewhat expensive due to postage costs and possible import tax but once fitted will give no problems. Their price for the thermostats are very cheap.
 
#121 · (Edited)
yup did mine last week ... took hose off dunked in some hot water and a bit of lube and the R5 stat slid in easily no mods neaded. ...ok so the 75 dosent warm up super quicly..it is quicker now ....its still a diesel..but it does now sit at half way once warm instead of the quarter mark the day before fitting..

This is a no brainer compared to an expensive inline stat and of course cheap to replace if the R5 stat goes ..and leaves the car looking totaly standard.
 
#122 ·
Just picked up one of the Renault stats from local parts supplier with the intention of fitting this in the next few days (before driving to Switzerland again).

How easy is it to remove the coolant pipe from the engine? The rimmer bros image looks like there is some form of "coupler" on the engine side of the pipe. For those that have done the mod - how does this come off the engine?

Cheers

Chris
 
#123 ·
Coolant pipe

The coolant pipe complete with the plastic end fitting is held to the engine by a wire clip arrangement. The loop is on the near side and you remove the wire clip which frees the hose end. It might be tough to remove since it has been on there for some time. There is an internal rubber O ring seal inside the plastic end so be careful. Of course you still have to remove the metal clamp on the rubber hose but it is easier with the whole assembly out of the car.
 
#124 ·
I gave up trying to get the hose out of the plastic moulding, for fear of doing expensive damage; the moulding seems rather flimsy, and I could foresee real problems getting it back together if they did part company. So instead I carefully cut through the metal band with a Junior hacksaw - taking care not to nick the rubber hose. Incidentally, removing the engine cover helps access, and to make it even easier I removed the inlet manifold!! Re-assembly is then straightforward, but I used a stainless steel jubilee clip as they are more flexible than standard ones, again because of concerns about the plastic moulding - and don't make it too tight, it's not compressing onto an aluminium stub. HTH.
 
#125 ·
Finally managed to complete this job yesterday evening and what a difference it makes to the engine temp!

I'd noticed when driving the car to work on Monday morning that the car just didn't seem to be getting warm - quick read on here and I had a nice and simple solution that wouldn't break the bank!

Like mikew8760, I tried for ages to get the pipe of the engine once I had removed the spring clip but could I get it to budge... nope!

Quick run into the house, grab the dremel and off we went.... only to find I'd managed to lock myself out of the hose in the process! Quick tript to the other halfs work (glad I noticed before I took too much of the car apart!) and back on with the job...

Damn, that bit of metal was tough - that or the cheap dremel substitute was just pants! Took me the best part of an hour and a half of dremel action to get the bloody thing off the pipe!

Once off the car it was back into the kitchen to apply heat and lube to the tube. Much cursing and swearing ensued until eventually I had the stat far enough down the pipe!

Refitting was easy.... I may however have overestimated how much coolant I would lose in the process and had purchased a 2ltr bottle of concentrate OAT coolant so now I have plenty of spare! Could of got away with one of the 1/2 litre bottles I recon!

Anyway, the trip to work was nice and warm this morning... watching the temp rise upto 91 and then sink nicely to an average 87 even with the heaters on full..

Be prepared for this job to take longer than expected (it is an 11 year old car afterall!).

Thanks for the tips and hints from previous posters on this nice little fix!
 
#126 ·
in line stat

Did mine last week and the difference is amazing,the temp. gauge goes up to halfway in about 3 miles,whereas before it took at least 10 miles.

If I may be so bold as to offer a tip....I used an empty plastic asprin container to push the new stat into the hose,it is just the right size.

BTW., I notice that some people are quoting actual temperature figures in their replies...how do they know these figures?
 
#127 ·
Did mine last week and the difference is amazing,the temp. gauge goes up to halfway in about 3 miles,whereas before it took at least 10 miles.

If I may be so bold as to offer a tip....I used an empty plastic asprin container to push the new stat into the hose,it is just the right size.

BTW., I notice that some people are quoting actual temperature figures in their replies...how do they know these figures?

They're using the onboard diagnostics that can be accessed using the top display and LH stalk. Can't remember the link but it's documented here and on the club site.
 
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