Volvo aqad40a thermostats

[parm]

can anyone give me any advice on how to change the thermostat/s on volvo aqad40a . Volvo salesmam sold me two thermostats but was had no advice on fitting and was also shocked to find there was two thermostats?

 

[Guest]

Easy, on top of the heatexchanger near the filler cap you will see 4 13mm head bolts, this is an alloy housing, remove it and yoyu will see the stats, if it is overheating it is another ball game, lots of work and can be many different things.

paul js.

 

[parm]

the engine is running slightly hot at about 90c and will only overheat if run flatout for about 10-15mins slowly rising. Was told to try theromoststs first

 

[Nab]

My Volvo TAMD40B (basically the same engine) is suffering the same symptoms i.e. generally running slightly hot but with temperature slowly creeping up when running hard with danger of overheating if the revs are not dropped back.
I've been thinking it might be the thermostat and would have changed it last weekend had Motortech had one in stock.
Please keep me posted as to whether you solve things.
Further advice on subject welcomed.

 

[parm]

i changed the stats (about £20.00) but did not help, then new impeller- still no help, then flushed out whole system and took heat exchanger off and was steeped in caustic soda to clear pipes- still no good and finally removed + replaced water pump and boat now running cooler but will still rise to 185 if pushed hard but it is reving to about 3700-3750 which i believe is a little to high if kept to 3600 no problems. but got bill for £550.00 for all this ouch!

PS the the two stats open at different temps 1 at 70 and the other at 78 i think. the engineer took the new 78 out and replacewd it with the old 70 so now two 70 c stats in engine

 

[Guest]

answer, blocked exhaust elbow im sure. no cooling water exiting engine slowing down flow through pump.
paul js

 

[eddieperkins]

have you checked the oil cooler? If the channels in it are choked up the cooling water will be restricted and less effective. Also agree with Paul, Check the exaust elbow, they rust up and restrict flow. Another possible cause could be with the water inlet on the drive. It can suck in air at certain speeds (if the pipe is split if I remember correctly) and reduce the effectivness of the cooling. I have the same problem and have yet to find the answer, although I have not started replacing pumps etc yet, so all I can do is wish you good luck. I am wonderinf if it may be the circulation pump on the engine that is to blame also, any thoughts out there?
Regaards
Eddie