[IrieLandy]

Heyup folks... just changing coolant and thermostat on 200tdi... got an allparts 88degree thermostat as a replacement, have just whipped out the old stat and i notice it is a "waxstat" which differs from the allparts one in the respect of having a rubber seal on the closing part, and also has a small one-way valve in the body of it.. a little ball-bearing which looks as if it would allow a small amount of coolant into the engine from the rad but not the other way. Does anyone know why this valve is fitted and is it necessary?

Cheers

 

[lynall]

The little ball is an air bleed, the waxstat is the best 200 stat you can get all the others are just rubbish,
Couple of months ago it took me an age to find a waxstat one, doubt you will find one now, if it worked fine I would put it back in.

 

[IrieLandy]

youre not wrong there! my mistake the replacement one is an "allmakes 4x4" --- i just thought i'd test it alongside the old one... and lo and behold the brand new replacement thermostat doesnt even work! the old one opens promptly at 88 degrees.. no movement in the other one whatsoever, even up to 96 degrees! waste of time

 

[IrieLandy]

Shame the waxstats are no longer made... have seen a few 82 degree ones for sale for classics, perkins, masseys and the like... might be a bit of low opening point for a 200tdi? wouldnt want fuel economy to suffer.

Here's what i did find that might be suitable:

http://www.paddockspares.com/catalogsearch/result/?q=err2803
-not a waxstat but looks to have the air bleed valve in it, described as quality aftermarket.. hmmm

http://www.lrspareparts.com/eshop/thermostat-8053.html
-no picture but has G on the code so presumably decent enough

anyway, my existing stat seems to work fine so will stick with it for the moment.

 

[IrieLandy]

Just a bit of backgound... i'm flushing the coolant system and putting in new coolant (last changed in 2011 as far as i can remember!). I've found that the engine runs hotter than normal lately when pulling loads (16' ifor trailer with bales of hay). have a kenlowe fan fitted but the thermocouple went south some time ago so have it on a manual switch. Interesting phenomenon is that when i first switch the fan on, the temp guage goes up quite a bit (no sure if this is an electrical issue with the guage or whether it's the extra load put on the alternator by starting the fan) - then it gradually creeps back down to just above normal but once its reached that temp i have to keep the fan on for the rest of the journey whilst worrying about the wiring/switch melting as it does get pretty hot even thought the wire and switch are well rated.
So hopefully a good flush and renewal of coolant will improve the situation. At least i know my stat is working!
I often wonder if i'd be better off with the original viscous fan hub arrangement rather than the kenlowe. That said, i'd like to get the kenlowe system working properly again with suitable relay, thermocouple, etc but thats a subject for another post!

Stay cool!

 

[chris-the-gerbil]

If you are worrying about the switch and wiring melted then they are not well rated! So I'd look at that and get some thicker wiring...

You fan is going to come on and be up to speed within a second, and the thermal lag of the cooling system wont respond that fast I wouldn't have thought - how long does this rise take? I'm wondering if they voltage change from the fan load is causing odd electrical gremlins - has the coolant sensor been swapped recently and it's wiring checked?

 

[IrieLandy]

If you are worrying about the switch and wiring melted then they are not well rated! So I'd look at that and get some thicker wiring...

You fan is going to come on and be up to speed within a second, and the thermal lag of the cooling system wont respond that fast I wouldn't have thought - how long does this rise take? I'm wondering if they voltage change from the fan load is causing odd electrical gremlins - has the coolant sensor been swapped recently and it's wiring checked?

it rises within a few seconds... so yes probably a wiring issue.. no the temp sender isnt new... i'll have to check the wiring and see what i find....

 

[lynall]

Shame the waxstats are no longer made... have seen a few 82 degree ones for sale for classics, perkins, masseys and the like... might be a bit of low opening point for a 200tdi? wouldnt want fuel economy to suffer.

Here's what i did find that might be suitable:

http://www.paddockspares.com/catalogsearch/result/?q=err2803
-not a waxstat but looks to have the air bleed valve in it, described as quality aftermarket.. hmmm

http://www.lrspareparts.com/eshop/thermostat-8053.html
-no picture but has G on the code so presumably decent enough

anyway, my existing stat seems to work fine so will stick with it for the moment.

G on the end is normally britpart code for genuine and to be fair Ive used quite a bit of it on stuff that cant go wrong and so far been good, not tried a stat though!

 

[lynall]

If your wiring is them blue crimp terminal you may like to know they are constant rated at approx 18amp and a decent sized elec fan may pull more than that during normal running and possibly 30 amps on initial start up, certainly I found a 20 amp fuse wasnt man enough.