GQ genuine thermostat's

[fnqcairns]

Just for interest here is my experience today. My car (96 td4.2) runs a nice and comfortable 1/3 on guage at easy highway speeds and on steep ranges at legal speeds in 34 deg heat will only go up to almost half on the guage-perfect!!
But coming down the range which was around a 20min long drive the needle dropped to below the bottom most line-too cold.

Anyway it's a new car to me so I assumed either the thermostat was stuck open or the previous owner had it removed. Today I buy a genuine thermostat and ask the guy at the time if this one was the only thermostat option listed genuine for this engine. It was.

I pull the old thermostat out which I strongly suspect is the original unit knowing this vehicles entire service history, it was stuck open around 1.5 to 2mm, then as I always do I test both the new and the old together the new genuine article would only open up to almost 1/3 the distance the old genuine one would even at boiling point

So I inspected both and guess what! Nissan has done a switcharoo on the thermostat designs, the new one has around 1/3 of the number of coils in the return spring so it's tougher for the thermo to open! and it will no longer open enough to provide enough flow as the original genuine one would in testing conditions -no way!!

I assume they did this to counter the stuck open problem but they didn't increase the opening power commensurate it looks the same from a cursory inspection.

Both have 76.5deg C stamped on them, no way the new one could do it at that temp if the old one used to. The new one cracked far later than the old one.

No chance I will be putting this unit in the car yet -it probably will not work well in summer here and will get too hot if I need to work yhe car.

Tomorrow I will take it back and see if I can replace it with another one, but I suspect it is working as designed and also in Nissan's overall spare parts favour!

Anyone with a hot GQ td 4.2 and running the genuine thermostat you have now probably found the reason or at least a fair chunk of it.

When I exchange the unit, if it operstes the same I will throw it in anyway and report back after a run what the go actually is old V new.
This vehicles cooling system is in as new condition.

Now I know restriction can aid cooling but this is too much restriction for summer down here and esp if towing and even if stuck in traffic in summer-guaranteed, it may simply be faulty, will find out.

cheers

[blkmav]

Maybe you were given the incorrect thermostat, mine works fine...

http://www.outerlimits4x4.com/PHP_Modul ... hp?t=51205

[fnqcairns]

No it's the right one, but the vehicle is a TD4.2 sorry forgot to add that. Will edit it in above.

cheers

[bogged]

No it's the right one, but the vehicle is a TD4.2 sorry forgot to add that.

cheers

remembering there are different temp thermostats too

[fnqcairns]

remembering there are different temp thermostats too

Yeah Ok I guess the redesigned engine 94 onwards (mine) could specify a different unit to earlier td 4.2 engines. Will try and sort it out a bit better tomorrow. both of these were 76.5C units and the only ones listed for the 96 engine. Curious

cheers

[Woop]

I think the part# for the Thermostat for all TD42's is the same. The genuine Nissan 76.5deg unit works fine on mine-i replaced it about a year ago. Going down a long hill with no throttle does exactly the same thing on mine. Working hard, mine comes up to halfway, and drops down to just below 1/4 coasting downhill.

Nick

[fnqcairns]

Well I now have a thermostat that works, the first new one has proved now to be faulty, this replacement one cracks at the right temp instead of quite late and opens 8 to 10mm at 100degC instead of half that so I expect no problems, actually it behaves with temperature in the sausepan on the stove better than the original old one out of the car + it closes all the way . I told them to throw the first one. Not re-sell. hope they listened.
Thanks for the replys.

Cheers