Grit Valve
2000 4.6 Vouge
I'm not slagging them off but iv known shops to pass parts as oem like there fuel pumps ect, that's why I say some investigating is needed ie buy from dealer and check numbers on moulds ect ect
I'm not slagging them off but iv known shops to pass parts as oem like there fuel pumps ect, that's why I say some investigating is needed ie buy from dealer and check numbers on moulds ect ect
i am interested to hear the science behind a timing issue causing overheating - can anyone explain ?
kevwill
Active Member
Purchased - yes. Problems - none. Changed 8 months ago.
Grit Valve
2000 4.6 Vouge
Late timing: If your ignition system is malfunctioning, late timing may be causing your vehicle to overheat because the spark plugs are firing the fuel/air mixture after the piston moves back down from the top of its stroke. Late timing alone doesnt cause an engine to overheat by more than a few degrees, but when coupled with other problems, it can bring the engine temperature to a critical point
Arrrrhhhh i see - so if the spark plug leads were on the incorrect plugs then this could have the same effect ?
jt_armstrong
Well-Known Member
It wouldnt help but i doubt it would cause overheating like you described. When i bought my '99 the engine sounded rough but I suspected duff plug leads (they were new and looked crap). I drove home 130 miles where i dicovered that the leads were crossed on 4 &6. She never overheated.
kevwill
Active Member
+1 agreed.
I had the same symptoms as you. Had changed head gaskets etc, waterpump, viscous coupling, thermostat, exp tank cap, rad flushed, system bled: was still overheating with top hose solid & ****ing out the expansion tank. Even took heads off again; head gaskets were good & no slipped liners. Was convinced had a cracked block or head. Turned out to be the new ****part viscous coupling. Changed for a better quality - problem sorted. I'd bought the best waterpump (metal impeller), but thought I'd cleverly save £20 on the viscous and go for the Britpart. Oh yeah, well worth it; 3 days of pulling engine to bits and pulling my hair out (mostly in the rain).
How did you find that it was viscous coupling? Was the bottom radiator pipe hot? Did it get colder after you changed viscous coupling?
Thanks.
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kevwill
Active Member
Yep it was all hot. New waterpump was working. When engine was hot at standstill the fan wasn't doing its job so temp was just rising. If your still getting a non hot pipe then you have a flow problem. Waterpump, thermostat, air block, or blocked port/channel or radiator. Have known someone who didn't fit the exhaust valley inlet manifold correctly which ended up restricting waterflow.
Are you losing water at all (other than expansion tank overflow)? Are you getting white smoke (water vapour) out of exhaust which would indicate head gasket failure?
Thank for answer.
I have bottom radiator pipe just warm, not hot. It doesn't overheat, doesn't loose water and viscous fan is pulling lots of air through the rad even when not heat locked.
As I understand, the purpous of radiator is to cool water. Hot water is entering rad via top pipe, and cooled water exists at the bottom. If bottom pipe is hot then rad is not cooling water. Right?
I have bottom radiator pipe just warm, not hot. It doesn't overheat, doesn't loose water and viscous fan is pulling lots of air through the rad even when not heat locked.
As I understand, the purpous of radiator is to cool water. Hot water is entering rad via top pipe, and cooled water exists at the bottom. If bottom pipe is hot then rad is not cooling water. Right?
kevwill
Active Member
Yep that's right. Rad cools the water but not to the extent that it will be coming out cold. Rad should be hot all over and bottom hose will feel warm/hot. If it's cold then you do have a flow restriction.
Did you fit thermostat No 3 yet?
Might be an idea to get a sniff test to see if there are any head gasket problems.
Did you fit thermostat No 3 yet?
Might be an idea to get a sniff test to see if there are any head gasket problems.
i am afraid not, not had too much time to work on car, am currently using it with thermostat wedged open - it does not cause any probs apart from lower mpg. I think that sniff test is next to see if i have exhaust gases in coolant on the belief that pressure is building up quickly and expansion tank is releasing pressure/coolant before the heat of coolant open thermostat - only thing against this thinking is: why does it not over pressurise/overheat when thermostat is wedged open ?????
kevwill
Active Member
Sounds like a decent thermostat will solve your problem. Here's hoping. Good luck and let us know.
