just realized i started in the wrong place

[Col. Mustard]

Hey everyone I'm Levi just joined the forum, haven't had a chance to look around but seems like a great place. I have a 73 c10 with a 250 and 3 on the tree, has been a pretty good workhorse until recently.

Couple weeks ago I found out the head was cracked, got a new one slammed in and got the truck running great. Only issue is the temp gauge The one on the water outlet/thermostat housing broke so went to use the one on the head. Using the stock wiring it would either bounce all over the place or redline within 5-10 minutes. Put a equus mechanical gauge in and sat at 195 for 20+ minutes idling, but as soon as I start driving it will fluctuate between 195-230ish. Took it to a shop and they are telling me that the sensor in the head is for a light (which I don't have) and the one in the tstat housing is for the gauge, at this point I don't care which is which im just tired of not driving my truck.

Anyhow thanks in advance for any help and hopefully I can return the favor sometime

[75chev4x4]

Ok I would say if u put an aftermarket gauge in with its own sender and it is still fluctuating and running hot ur prob is with the engine. Did u burp the radiator when n u swapped the head and are u losing any coolant? Anything else weird going on with the engine no heat from heater?

[Col. Mustard]

I had burped the system, and the shop I took it to did as well, plenty of heat from the vents...only thing I haven't done is get a heat gun on it and verify how hot its running. Talked to a guy and he says that the 195 range tstat is too much, heading out to get a lower range one and a heat reader.

[75chev4x4]

Did you change any hoses or anything? I had same thing hapen once and I had a plugged heater return house and it would get hot after 5 min everytime. Yea maybe try new tstat might be too hot or could be bad one all together.

[75chev4x4]

And your coolant level looks good ? Your not loosing any and your oil looks nice and black or clean? Hows your radiator look?

[Col. Mustard]

coolant and oil both are staying clean, doesn't look like I'm losing either. had changed one hose cuz it had split, but other than that I flushed the system before putting the new head on.

[75chev4x4]

Yea try the heat gun maybe the gauge is wacky, hmm. Wish I had some time to come up and help u ur just across the bridge from me. Youll get it though.

[Col. Mustard]

hopefully its the gauge or something simple, getting really tired of lookin and not driving.. appreciate the offer I'll let you know what I figure out

[Col. Mustard]

so it looks like it was the tstat, put in a 185 range and ran it for a good half hour, temp gun got up to around 220-230 on the head right by the sensor, plug side was around 180-190, no fluctuation on the new gauge while driving...goin to do a couple more test runs before I start driving regularly