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Diesel engine temp not rising
tegwin - 19/2/18 at 12:45 PM

I have a VW T5 with a 2.5TDI 174hp engine.

The thermostat is clearly dodgy as the van only gets up to 90c when you are pushing it, at B road speed the temp on the gauge fluctuates from 55-85 depending on if im going up or down hill etc. Running the cabin heater lowers the temp more.


Will I be doing long term damage to the engine driving it at anything less than the "normal" 90c?

I do have a brand new thermostat sat here but I can't swap it easily as somebody in the past has clearly tried to remove the thermostat with the wrong sized tool and trashed the bolt heads... No way in hell I can get a drill or a welder in there...id have to remove the turbo and intake manifold which would end up being an expensive job!


luke2152 - 19/2/18 at 01:07 PM

Can you put an inline thermostat such as a landrover one in a hose


r1_pete - 19/2/18 at 04:13 PM

The engine will suffer running as it is, egr and dpf at least, which depend on heat to keep carbon build up down, as with other areas of the engine. Long term it will soot up.

As above can you fit an inline stat in the top hose as a temporary measure??


tegwin - 19/2/18 at 04:27 PM

That was my fear.

I could potentially fit an inline stat....

Could having two stats in series be too much of a restriction to the coolant flow resulting in an overheat situation though?


perksy - 19/2/18 at 10:14 PM

In line stat or could you make up a radiator blind as a temporary measure ?


obfripper - 19/2/18 at 11:36 PM

They should be the normal vw 10mm headed bolts that also have an internal 5mm hex inside the head - if you can get a 6 sided spanner and a 5mm allen key on at the same time you may get enough leverage to start moving the bolt.

If yours has multispline heads (should only be on the union below the thermostat but may have been mixed up), try some of these type extractors in the damaged head.
https://www.ebay.co.uk/itm/1-2-Screw-Stud-Extractor-Remover-Set-Reverse-Thread-Easy-Out-3-11mm-10pc-AT07/400975012948

Also have you had any issues with oil in the coolant? - it's normally oil cooler related and causes the rubber part of the thermostat plunger to plim up and the thermostat to not fully close.

Dave


tegwin - 19/2/18 at 11:47 PM

Hi Dave.

Yes I had an oil cooler fail causing oil in the water and then a brand new pump failed putting water in the oil....

The garage that did the work flushed evythibg out but clearly couldn’t get the thermostat out sob didn’t bother. I’d have changed it as part of the repair job myself but hey ho...

Took it back to garage and was told the temp not rising was normal.... odd that it wasn’t like that before.

There’s not much room between the head and the thermostat housing so not sure what I can get on it but will have another look tomorow and see what tools might work...if i can get leverage i hope the bolts don’t snap!


dinosaurjuice - 20/2/18 at 11:15 AM

I had a thermostat on a Citroen Picasso which gradually got worse at closing as it got older, so its probably just that. Made a noticeable difference to MPG after i changed it!

Also, is it a caravelle? IE does it have heating in rear too? if so they are notorious for not warming up in cold weather when trying to heat interior. particularly if the auxiliary heater is faulty.


Mr Whippy - 20/2/18 at 12:34 PM

how about the old solution of blocking off some of the radiator? Most cars engines run a lot colder in the winter tbh, I've got a sheet of 3mm plywood on the front of the Landys rad held on with tie wraps with a 1ft square hole in the middle, warms up so much quicker, fine in the city with no overheating


ss1turbo - 21/2/18 at 01:45 PM

Can you get an Irwin bolt remover on there? I've removed a very chewed sump plug (was only a 13mm hex to start with, then rounded by a gorilla with an impact wrench, it seemed) and was very impressed.

Starter set: https://www.toolstation.com/shop/p81815
Expansion set: https://www.toolstation.com/shop/Automotive/d60/Socket+Sets/sd2938/Irwin+Bolt+Grip+Nut+Remover+Set/p63045


tegwin - 21/2/18 at 07:04 PM

No luck with the irwin tools but a cold chisel and a lot of bruising to my hands got the bolts out and I now have a fully working thermostat.... loveley!


Mr Whippy - 22/2/18 at 07:34 AM

quote:
Originally posted by tegwin
No luck with the irwin tools but a cold chisel and a lot of bruising to my hands got the bolts out and I now have a fully working thermostat.... loveley!


nice one