First Time Head Gasket Replacement 1988 1.3l

[Mike McKown]

One day you can run down the interstate at 75 mph and the engine stays cool, the next day, it overheats. Doesn't sound like a clogged radiator to me.

[kartracer46]

One day you can run down the interstate at 75 mph and the engine stays cool, the next day, it overheats. Doesn't sound like a clogged radiator to me.

I agree, the cooling fan and switch need to be diagnosed first before looking for a clogged radiator.

[Mike McKown]

I don't believe it would be a fan problem either. The engine shouldn't get hot enough to turn the fan on, not that the fan could do any good at highway speeds.

I read the OP put in a new thermostat, but I believe the thermostat may be his problem.

There's two places in the cooling system for the engine to discharge heat. One is the radiator, the other is the heater. Engine coolant won't flow through the radiator is the thermostat is stuck but it will flow just fine through the heater. Not enough flow though to keep the engine cool.

[Ohh!]

I think Mike McKown has a good point, but you said you removed the thermostat and it made it worse. You should drop the radiator hoses and flush the radiator. Probably good idea to flush the block too. The thermostat will hinder the flow but crap should still come out if you flush from the bottom. Check all your pipes for corrosion (bulging at hose clamp). Maybe your core/freeze plugs have built up corrosion limiting coolant flow through the block? I just pulled some steel ones from an old datsun, had like 5mm build up. water pump given up? but you saw coolant flowing. ... definitely flush it man

[1988redfordfestiva]

Here a great idea get a temp read out gun and point it to the things that might be the issue hey for $25 at harbor freight you can't go wrong ..
Anyways i have one and just remembered that's what i used when i was having my fan issue..
also if u get a great deal of time what kind of water pump did u put in ?