alr37115

I had the NSS and the thermostat (had the coolant flushed and filled too) replaced yesterday. I drove to school today(about 15 miles), suddenly the temp jumped from a little over 210 to 260 and the check gauges light came on. It went from max back to around 215 for a couple a seconds then jumped back to max. The hose around the thermostat isn't collapsed, heater core is clear, the radiator cap is brand new. Could it be the radiator itself? Coolant temp sensor? All of the above? Any thoughts, help and/or past experiences with this issue is very helpful and appreciated.

rgr4475

What kind of thermostat was used? Perhaps it was a faulty one out of the box?

Firestorm500

Temps won't actually jump around like that. Somebody knocked a wire or plug loose on a sensor somewhere.

The shop that did it needs to check their work.

And apologize for the heart attack they gave you.

djb383

Remove that new rad cap when the motor is COLD and make sure the rad is full to the top. The bottle should be about 1/3 full, motor COLD.

alr37115

I'm not sure. I'm pretty sure it came from either O'Reilly or AutoZone. I took them the NSS but the shop ended up getting the thermostat and gasket. I haven't had anymore problems that were being caused by the NSS. It shifts from 1-4 no problem, the transmission doesn't have any slip in it. It gets up and scoots... this sudden overheating issue concerns me.

Here's what I've had done/done myself so far:
Oil Change(Long overdue by the looks of the oil they drained)
Transmission Filter/gasket (the gasket was non-existent)
Input shaft main seal (took care of the transmission fluid leak)
Thermostat/gasket
o2 Sensor on the back of the exhaust
Input Shaft VSS (Mistook this for the range sensor)
Coolant flush/refill (It was filled with straight water)

Could it be that the radiator is rusted out? Bad water pump? I'd rather throw a couple hundred dollars at it than a couple thousand for a new motor.

If the thermostat is bad OOB that's a manufacturers fault, and I should be able to take it back to the shop and have it replaced on their dime right?

Thank you for your insight into my issue.

djb383

Again, when the motor is COLD, make sure the rad is full to the top. The entire cooling system can be replaced for <$250 in parts.

Firestorm500

Please, for your sake, reread post #3 and do that first before going off the deep end with wild speculations.

djb383

^^^^^#3 & #4.

alr37115

The radiator was full, and the bottle was 1/3 full.

alr37115

Thank you guys for the advice and insight. I'm glad I joined this forum. Apparently the PO failed to realize that cooling components won't survive when the only thing in the system is straight water especially when it winds up sitting on some dealer's lot for a couple months.

I may not know a whole lot about vehicles but I know enough to make sure that the coolant, oil, trans fluid, plugs & wires are vital to the continued proper operation of any vehicle. I can reach most things on the XJ without even having to move anything or jacking up the vehicle so when I finish un-f****ng the PO's lack of either maintenance or lack of give-a-s**t. I can finally keep up with the routine stuff.

Michigander

I say change the Water Pump if you have not yet ASAP.Last thing you want is to over heat it. Temps should not change like that .I say its starting fail.

alr37115

It's in the shop right now for a water pump replacement. I'm without it until sometime tomorrow. I've had it for 2 weeks, and from what I've gathered, the PO really had no concept of routine maintenance... or any maintenance for that matter.

I've replaced a speed sensor, input shaft seal, trans filter/gasket, one o2 sensor, the NSS and now I'm working on the cooling system since the PO had nothing but water in it, and it sat on a dealer's lot for who knows how long until I bought it. The transmission and the motor are good to go... short of plugs and wires, which I have in the cargo hold.

I have to go through emissions once a year where I live, so a CEL will fail regardless of what it is. I have seen some real "bang up" "bad round of bumper cars" vehicles where I live but they're still on the road because they pass emissions, and if they don't, people have resorted to registering them in a county that doesn't require emissions testing in lieu of fixing them.

alr37115

They need to have a dozen wings and Mt. Dew waiting for me when I go to pick up my XJ tomorrow as a "sorry we spooked ya" gift. They're a great shop who I've been working with since I moved here back in 2009. They've worked on my '97 Mustang, my '97 Riviera, and now my XJ. I reminded them to check, double check and then check everything they did once more... If I had any idea what I was doing mechanically, I would DIY it but I'm a computer tech so I leave the vehicle work short of changing fluids, electronics, plugs and wires, and wiper blades to the pros.

djb383

Of all the cooling system components, the radiator is the only one who's sole function is to dissipate heat. If it's been run with water only, u can bet the small passages in the rad have at least some internal solid scale build-up that cannot be flushed out. The rad must be "rodded" out to remove the scale build-up.

Firestorm500

Nowadays radiators are so cheap we just replace it rather than vat it.