Hello.
Last season in summer, it was 100deg out. She did just fine.
It's now about 20-30deg. Driving on the freeway with that chill factor and the fact that the radiator fan is spinning fast, I'm not sure how it's even possible.
But my temp gauge will climb up very near the H. If I let her coast in the cool air, it will come back down. My heater is working and my coolant level looks good.
Fresh 10/30 dino oil is in but this has been going on for a couple months now (having to monitor it). Before the issue we used 15/40 oil as 'brake in' I guess, but I doubt going to normal 10/30 is the issue. Just information.

My plan is to flush out the rad, replace the thermostat this week. It's just scary, thinking 100deg is coming again.

What else should I be looking at? Or what is the most likely reason?
Thanks.

 

Need to make sure it's not just a gage issue basically. If it IS overheating at 20F down the highway, you've got problems. Is it spitting coolant? Engine knocking?

Is the water pump old i.e. impeller corroded out and not moving any coolant, check for spring in lower hose to prevent collapse etc. Use only Motorcraft thermostat, lots of ersatz schitt being sold these days if you read the auto forums and causing problems. Most engines have block drains, pipe fittings. Open these and dig out with ice pick to get block thoroughly flushed.

 

Thanks man. No spitting coolant and no knocking. The motor is 'newish', in that it was refreshed from the crank -up. New cam, built up again. New water pump as of like.. 1.5yrs ago. But I'll go motocraft stat for sure and check my hoses for tightness. But the hoses are new as well as all hoses about the same time frame (2yrs max).
I'm not sure about the block drains.

 

What I mean is, there is usually a spring installed in the lower radiator hose, to prevent suction or whatever at high speeds from collapsing the hose and restricting flow.

It sounds though - maybe - it isn't really overheating? Could be a defective ICVR - are any other gauges inaccurate or erratic. If it IS overheating, don't overlook simple stuff like a loose belt. You're doing all the right stuff sounds like.

 

Ok thanks. I assumed a loose belt would be a loud belt, those are new too.. but yes I'll do some stat/change/flush and see where we at.
The voltage regulator is probably 40yrs old. But all other gauges are working properly.

 

Get yourself one of these, they're invaluable for this kinda stuff:


Does it 'overheat' while you're in the driveway? If so, point the temp gun around and see what it's reading at various locations. That should shed some light on what's going on.

 

Ha, cool. Yeah I should have one.
Yes, she will climb up while at idle and 'warming up' in the morning. Gauge shows 'cold' at first.. climbs normally, but keeps on going up way too close the the H for what I think is normal.

 

I would also add a good mechanical temp gauge. That way you can actually see what the temp is going to.

 

Thanks guys, think I got her licked. It was probably just the thermostat.

Ended up, removing the thermostat, went to push on it and the first push there was a 'click'. Then just hard to push open but I think a 190deg is anyways.
Cleaned the mount area well. Stuck a hose in the block and flushed her out well.
Stuck the hose in the rad and flushed that out too. When I stuck the hose in the rad and watched the green flow out of the block, I'm pretty sure I saw streaks of brown coming out too. I even added in some probable snake oil, "Radiator cleaner". It was only $7. Looked and smelled like water. Flushed that all through via the instructions.
Installed new thermo, just a bit of anti-freeze and mostly water. Watched the gauge slowly climb up and as soon as it hit the 'N', boom.. dropped. That must be the 190deg mark.

The only reason I posted on here about was that I was under the assumption that if the heater worked, that means the stat is working.. but I guess not.
I'm not even sure why I need a stat in the summer.. she drives fine without. But whatever.

SHE GOOD!

 

An engine needs a thermostat, because it is desirable for an engine to reach N.O.T. (normal operating temperature) just as soon as possible. This not only increases fuel mileage and efficiency, it decreases pollution and engine sludge/acid buildup, and decreases engine cylinder wear by about a third. You can tell an engine that has been run a long time without a thermostat when the valve covers get pulled. Always run a thermostat, imo. Always run a Motorcraft or quality thermostat, like so much today lots of counterfeit parts are in the system. There's a fair amount of labor involved in a good engine flush, don't install junk for your efforts.

 

Makes sense man.