overheating problems!!

[grtcrowd]

We have a 93 Toyota Pickup extended cab 4WD 22RE with serious overheating problems. It was rebuilt some 20,000 miles ago due to the same overheating problem. At that time the head was totally rebuilt, valves replaced, cooling fan replaced, all hoses replaced, thermostat replaced....we've even replaced the tacky plastic top radiator with a nice new LARGER metal one!

Anyone got any new suggestions!?

P.S. Seems the worst problem does occur now when the car is sitting in traffic during 70+ degree weather.


Thanks in advance for any solutions or suggestions.

[§©RÉWßã£]

???
I take it the fan clutch is ok.
try getting an elecric fan.

[eduardo]

hey grtcrowd, have you checked to see if you've got the correct thermostat? just take it out and it should say on it the temp range at which it opens! if you live down south you'll want one with a low rating so it's sure to be open when the water starts gettin warm. since you'll have it out anyways i'd just go and get a new one and what ever it says on it just get a new one with a lower rating made for hotter weather! you might also just preventively buy a new cheap cap "without a safety pressure release valve" just to insure you're getting max coolant pressure! i'd also flush cooling system out several times using just water since it's cheaper by draining present coolant & discarding and then filling with water, then run it around the block a little but don't let it get too hot cuz the water's not nearly as good as antifreez! then get it home, let it cool a little then drain it then repeat about 2-3 more times then fill permanently with 100% antifreez! i don't know when you say the engine was rebuilt if you mean the block was totally stripped and machined but if not then by chance it could have not been cleaned properly by toyata and still have sand in the block clogging up the coolant channels! if the rebuilder did do the block then there might be a good chance of this since rebuilders vary in compitence as about the same as painters or guitarists! you might have had a modern abstract moron instead of a devinci or dali! if so then the repeated flushing should help somewhat. you might also want to install an after market oil-cooler. a truck that's not pulling anything shouldn't really need one but they definitely can't hurt unless you don't want to put out too much money. they run about $80.00-$100.00 but they're pretty easy to install! the only trick is just figuring out where to mount it but you want to insure good air flow! good luck!

[eduardo]

grtcrowd, another thing i thought cuz this happened to my uncle who had the small v-8 in a '40 merc rebuilt was that the rebuilder bored his cylinders out too big thus reducing the space between the cylinders so that there wasn't enough block mass to properly absorb the heat so almost all the block heat was directly transferred to the coolant and the coolant got heat overload! with a cast iron block the block and the coolant both share cooling responsibilities.

[suv]

Was the water pump replaced at the time of the rebuild? The fins on the pump can wear off and cause poor circulation. BTW, 50/50 mix of antifreeze and water provides better freeze and heat protection than straight antifreeze.