Running warm.

[Eveready]

My suspicion would be clogged radiator because the temp goes down when the revs go up, forcing more air past the radiator. If thermostat doesn't fix it a good radiator rebuild would be on my radar.

Please post when you chase it down.

 

[Tavi]

I looked up what NAPA is showing for a '94 with 454. They're claiming part number THM-531090. It's a little guy judging by the photo--but they don't list the flange diameter. The Buyer's Guide shows applications for '91--95 K2500. You say you know it's "in correct", and I agree. 'Course, I've been wrong before.

I'm fairly sure you actually need NAPA # THM-183 or the equivalent. NAPA shows the flange diameter as 2.126". That would be "the" common thermostat for GM going back to about 1935, along with some Ford, some Chrysler....even imports like Alfa Romeo, Jaguar, and Austin used that 'stat.

Yes. The little T-stat is correct for the TBI 454. The first time I bought one I promised the parts store guy I would be back to exchange it.

 

[TheBeast]

Well, as of now, she peaked at 210 last night on the highway. I changed the radiator cap and then we headed out of town for dinner. Maybe t-stat and see what happens.


Sent from my iPhone using Tapatalk

 

[TheBeast]

Well, Tapatalk says you do not have permission to reply. Great. Anyway, here’s what I’ve done so far, part verification and part replacement.

Replaced:
Fan clutch
Radiator
Hoses

Verified:
Shroud is in great condition
Water pump is newish (a lot cleaner than rest of engine)

Also, sitting with ac on up here in bear, 6800ft at work, she idles at this pic.
Down the hill, roughly 2200ft she increases until about 220-230, temp up here was 80, temp down there for test was about 85.

I just bought another t-stat, so installing after work.

You must be registered for see images attach

 

[TheBeast]

And I will add, I live in the mountains, she doesn’t overheat up here, flat ground or towing, up hills and down hills, nothing. Down the hill she has trouble on flat ground!

 

[east302]

Well, Tapatalk says you do not have permission to reply. Great.

Regarding Tapatalk, they told me it is an issue with the plugin in this forum. No idea how that is fixed, but I posted a thread to see if there was a solution.

https://www.gmt400.com/threads/tapatalk-issue.42208/#post-1012505

 

[whiteboyslo]

Re: reading CTS, you need an ALDL scanner. I have one from 1320 Electronics. Love it.

Mike