Hi.I've just bought a masterace 4wd off ebay which had an overheating problem.I found the problem was being caused by the water pump not turning (the outer pulley was turning but the pump itself was not engaging).I cured the problem by running a permanent posite supply to the cable at the back of the pump from the ignition.What I need to know is what is supposed to supply this and where can I find it on the engine.I assume there must be a temp sensor that has failed.
- (#14391) Dafydd Rees, 4 Dec 04 11:53
Eh!!
Townace waterpump is driven by cambelt. Don't know where you have found this electric waterpump, I assume someone has fitted it to try to cure the cooling problem.
Overheating could be down to cracked head though, common on 2CT.
Regards Rob.
- (#14391) Rob Drinkwater (CAFTEC), 4 Dec 04 12:35
I'm new to the toyota masterace having only just bought one.The water pump is driven by a belt from the crankshaft pulley.At the back of the pump are 2 wires negative and a positive switched.With the engine stationary I am able to turn the water pump independant of the pulley.When the positive wire is energised the water pump engages the outer pulley.From the way it is fitted and the wiring it appears to be a standard fit on the vehicle and not a mod.As I said earlier having established a permanent supply to the pump I no longer have overheating problems with the masterace.If you want a photo of this pump I'll supply one.Thanks
- (#14391) Dafydd Rees, 4 Dec 04 13:09
eh!!....??
I'll correct myself about the location of the 2 wires. They are actually situated behind the pulley which drives the pump.I've browsed the previous questions with regards to overheating but none seem to mention these wires.Is it possible that my masterace is a one off o'r have they been missed?
- (#14391) Dafydd Rees, 4 Dec 04 13:22
methinks the pump you refer to is actually the airconditioning compressor. as rob says, the waterpump is buried under the timong cover, driven by the timing belt.
why should engaging the aircon stop the engine from overheating? the a/c has additional electric fans that help to blow cooling air through the condenser/ rad pack.
i'd guess that you're actually suffering from two problems- failure of the a/c controls, plus a slight overheating issue. you'd want to flush the cooling system, replace thermostat and rad cap, then look closely at the visvous fan coupling.
hth
- (#14391) david miller, 4 Dec 04 13:38
Looking at the engine front on, where abouts is this water pump?
- (#14391) Clive (Bristol), 4 Dec 04 13:38
Yes, I agree, the pump in question appears to be the aircon pump and the postitive feed is making a permanent drive to the magnetic clutch, mounted on the front of the pulley. However, when correctly wired, this clutch should only operate when the main air blower is working. Unless there IS another pump fitted, a check on the hoses, to and from this pump, are likely to reveal it's connections to the aircon system, and not the cooling system. The excellent tool, for the Masterace & Townace owner is the engine manual, code RMO25E, available from your local Toyota dealer, and this will show the water pump and ancilliaries, in great detail. As David says, the aircon ancilliary fans (two) mounted above the front, horizontal radiator, are no doubt being triggered by an unusually high head temperature, via one of the two sensors, at the front of the head, adjacent to the rad cap/filler neck.
- (#14391) John Davis (Leics), 4 Dec 04 14:20
Does the air conditioning compressor have a main feed pipe that is directly connected to the bottom of the radiator?From my experience of working on other vehicles i'd say this is a water pump.Yes i agree a magnetic clutch is getting activated but this is definately a water pump which is driven by a belt and not the timing belt.My masterace is a 1990 import which says its a 2ct engine.The pump I'm refering to is just below the expansion tank(right hand side looking from the front).
- (#14391) Dafydd Rees, 4 Dec 04 15:10
Look again. The hose you refer to actually goes onto the thermostat housing, which is in behind the aircon compressor...
- (#14391) david miller, 4 Dec 04 15:22
Then I stand corrected.I'll now have to try the advice earlier and see if I can cure the problem.
Thanks
- (#14391) Dafydd Rees, 4 Dec 04 15:31