Running hot, is it toast?

Well here is what I did. I bought a rolled 99 XJ to use for parts for my 91 with no motor. I was a little worried about it being a rolled vehicle when I bought it. Wasn't able to drive it much but the thing started up and idled like a champ. I was able to drive it around the yard and into the garage. Now I've swapped the entire wiring harness, engine, AW4, NP231 and interior into my 91. I gave my radiator to a buddy in a tight spot, so I pulled a junkyard radiator when the time came I needed one. Now I started it up and it still idles like a champ, but as soon as I get it going around 30 I start getting some valve train noise. Then if I drive it a couple miles it runs around 210-220. Then, without notice it jumps to 250-260. I'm also running around 45psi oil pressure. I don't have much experience with rolled vehicle's engines. I guess I'm just looking for advice on what you would check first.

BTW I just noticed that the Coolant Temp Sensor is cracked in half. I'll be getting a new one as soon as I can. It is still connected and giving a readout.

Any help would be appreciated. :helpme:

run a compression test and go from there. Check and make sure your drivetrain bolts for driveshafts are tight and the ujoints are greased or check if there bad.

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I'd bleed the entire cooling system again and cross my fingers. The spike in temp sounds like an air pocket.

Shorty said:

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I'd bleed the entire cooling system again and cross my fingers. The spike in temp sounds like an air pocket.

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Yeah I'm going to do a compression test and bleed the cooling system as soon as my buddy shows up with his test set. Thanks for the fast responses.

If it was a 99, it should have rollover protection and automatically shut off the engine, but nothing is guaranteed. If it ran upside down, bad news. Like others said, do a compression test. How many miles did the donor motor have on it?

Well it's running good now. Bleed the coolant and it's finally pumping water. :clap: It's running like a champ. Now I just need to get new o2 sensors, weld up the exhaust, and fix my cracked headers. Thanks for the help.