Hope all is well with the rest of you.

Here's my problem -
1998 w/ 4.6 289,000mi. Bought one year ago.

1) Heater has never worked.
2) Truck started overheating months back, but it was because of an oil leak.
3) Currently, the truck overheats after about 25 to 30 minutes from a cold Summer start. I have replaced the thermostat, radiator (to a two core). Mechanic pressure checked and no sign of a blown head gasket.
4) Oil dip stick reads Max/full.
5) I drove 30 mintutes on Friday and it started to overheat and gush out the overflow. I let it sit for one hour, added a quart of oil + half a gallon of water and drove the same route back. No overheating at all. BUT, I accidentally drove back with the radiator cap off!!!
6) When I changed my radiator I also inspected and flushed the hoses and cooling system. The guy I bought it from used Dexcool and when I flushed it the stuff that came out was a bunch of flaky rust looking chips/crust.

Any ideas where to look next? Water pump, pressure problem with radiator cap... I can't keep buying a gallon of Dexcool EOD.

Thanks in advance for any help and/or advice!

 

Water pump fins have been known to corrode completely off. That seems to be the best/cheapest place to start.

 

This is where my mind is going too

 

First of all Dex cool is made just for gm vehicles. Just because the dumb *** previous owner put it in does not mean you should. I would have system professional flushed. I don't know first hand if the Dex cool will mess up our trucks.
Next would be to replace the water pump. Or maybe do water pump first and then have flushed.

 

Thanks! In the winter below 45 degrees the truck wouldn't even get to its normal operating temperature until about 40 miles of highway driving.

Also, the truck is losing coolant even when it doesn't overheat. A lot, but I can't seem to find the leak once I park the truck.

I'll have someone inspect the water pump this week.

Thanks again.

 

Pump...the only thing left.

It would leak a tad as well if its gone bad.

 

I would start with a new water pump and thermostat. No telling what the dex cool did to them. The symptoms are telling to start there

 

Oooooooh DEX Cool in Ford....huge no no...my buddy did that and it corroded the crap out of the water ports/jackets within the intake and block....real nasty stuff!! It caused blockages creating hot spots in the block ultimately making it overheat. Took tons of pressure to unblock the whole system and a new rad.

 

Wow, so a new water pump + good flush & replace with regular green antifreeze would be best? I know mixing Dexcool with regular antifreeze causes it to sludge up. Would a good flush get enough Dexcool out?

 

They do make a kind that can be used with either type just in case the flush doesnt get all of it.