The temp gauge on my 1991 2.0 TD Townace suddenly dived into the red after a previously smooth 2 hours on the motorway last week. AA sent it home on a truck, saying suspected cracked head/gasket. A couple of days later I tried it - got to get the kids to school - and found that driving around town was completely normal - no overheating, maybe a bit more water loss than before. A mechanic friend said it couldn't be the head if it was running so normally and smoothly, but I've found it's still getting too hot at motorway speeds. I had replaced the rad cap - thanks to this brilliant site - and yesterday put a new Toyota thermostat in, but its still running too hot at speed. I'll try the fan next, but should I still be wondering about the head, cos I am....
- (#12217) Raheem, 21 Jul 04 05:15
Hate to be a killjoy Raheem but it does sound like it's the head. It's the same symptoms I had when mine went. Have you tried running it from cold with the rad cap off? Check for bubbles coming up through the coolant. If you do then it's a sure sign of head trouble.
- (#12217) Ian Dunse (Derbs), 21 Jul 04 05:36
raheem, there is a great deal of information in the archives and many checks which you can carry out. your symptoms indicate a number of areas to investigate.
1. did you re-fill very slowly after fitting the thermostat etc? there could be air in the system.
2. is the expansion tank filling on warm up, and the
level falling on cooling?
3 check the fanbelts for slippage under load.
4. check that the fan is turning, when hot, at speed,
with the passenger seat up. also, immediately
after stopping and turning off the engine, check
that the fan/coupling assembly has some resistance,
ie, considerably more that in the cold condition.
5 with the rad/filler cap off, and a little bit of
throttle, is there excessive turbulence which
will cause the coolant to be ejected from the
filler neck ?
if everything seems normal, it might be that there
is a slight coolant leak, from a hose connection or
joint, which only shows up when the system is hot and
that your thoughts on admission to the cracked head
club might, hopefully, be premature.
- (#12217) John Davis (Leics), 21 Jul 04 05:44
Overheating at motorway speeds sounds like the viscous fan is failing. This could be a slipping belt or a failing coupling. A good sign that the fan is at fault is to slowdown abit so that the revs are less than 3000 and see if it cools. If you have cracked the head an indication is that your coolant will start to turn black. This is because of the soot.
- (#12217) dave Bright (Bournemouth), 21 Jul 04 06:32
Not to disagree Dave but I've never seen the coolant go black on mine, plus if there IS a head or gasket problem it'll overheat at speed as the engine is working much harder than around town. The overheat that Raheem has experienced is due to lack of water following the prolonged high speed run. You'd need to do way more than the same miles round town to lose the same amount of water...
But on the upside, there's no guarantee that more than a skim and a gasket is needed until you've the head off and can verify that there's a crack...
- (#12217) David Miller, 21 Jul 04 10:58
I'm not disagreeing either dave, just trying to suggest that the fan maybe at fault, and would be a good starting point given the cost and work involved in a new head gasket. BTW the coolant on mine went as black as black can be when my head cracked last year, but I suppose it depends where the crak is.
- (#12217) dave Bright (Bournemouth), 21 Jul 04 11:08
Well, refilling then looking for pressurisation is conclusive- no pressurisation= fan problem, pressurisation= head or gasket...
- (#12217) David Miller, 21 Jul 04 13:12