Running warm on highway

[NocturneVoyager]

One thing I've noticed on my recent roadtrip is that when I get above 65, the temp runs on the higher side of normal and stays there. It doesn't overheat into the "hot" zone, but it got scarily close. Is this a stuck thermostat or something else I should be looking into?

 

This is on my '86 Xt - 1.8 engine

[Frank B]

Most likely the radiator. Get one for a turbo model, with the thicker core. there really isn't a two row available, just the core thickness is different. With the thicker core, and working fans, you will never be able to over heat that engine.

[nipper]

When in doubt start cheap. Replace the T-stat and the radiator cap (do the cap first). At this age, a decrepid readiator (clogged or missing cooling fins or both) wouldnt be surprising.

 

nipper

[idosubaru]

my suspicion is usually on the radiator with almost 20 year old subarus. but like nip said the thermostat and radiator cap are so cheap and easy to replace, that it's a great idea to just replace those first. go Subaru only on the thermostat - the difference is amazing, just looking at them.

 

for the radiator have a look at it first and see what condition it's in. are the fins there, is it rusted bad, falling apart? if it looks good then you could attempt flushing it out, good chance it's clogged. though radiators can be had for $80-$100 so replacement is preferred in most cases.

 

another possibility is the harmonic balancer (crank pulley). they have a thin rubber concentric ring in between the inner and out portions of the pulley. the metal can separate from the rubber and cause the actual outer part of the pulley not to spin as fast as the inner part. this can be a real challenge to narrow down if you don't know to look for it. draw an easy to see line (that won't get rubbed off) across the face of the crank pulley with anything...marker, paint, whatever. run the car for a day or week and then have a look at it.

if it's fine the line will look like this:

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if it's not the line will have broken due to the pulley having separated and the line will be out of alignment like this (in circular fashion of course):

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[spokanesoob]

my car had this problem for a little while, i just got a new radiator and Cap. solved it. good luck!

[merkatroid]

+1 for suspect the radiator. Mine was running hot on the highway. Replaced the radiator with one from my parts car. Runs correctly now....or is that for now?

[True2Blue]

+1 to the rad mine did the same thing then overheated while goin up a hill on the highway:mad: i replaced it with a rad outta a 91 and it runs cool now:banana:

[Durania]

I did water pump on mine two weeks ago and seemed to help it for a while. I noticed today that my radiator is cracked and is draining a little bit down onto the ground and getting warm running around town. Got to replace it tomorrow with one out of my EA81 hatch. Hope that fixes it.

[GeneralDisorder]

Verify the temp with another gauge before you do anything. DMM with a thermocouple is useful, or a laser temp gauge.

 

GD