Just picked up my 03 S type today and have had loads of questions answered by this forum already. So thanks a head of time.

I am looking for some help with the engine running hot on the highway. Seems odd, but once I get up to 55 or higher longer than 5 minutes, the temp gauges jumps up to 3/4 mark and the fan kicks on and stays on for about 10 min after the car is shut off. Is this normal? The car itself runs great and when I lift the hood the car doesn't seem hot. Bad thermostat maybe? Also there are no error codes showing on the dash.

Any advice would be great.

 

My guess is a partially open (stuck) t-stat. What is the status of the coolant level?

Are your hoses appearing 'larger' than normal, when running can you squeeze any of the hoses leading to the t-stat housing?

Check and make sure you have a very clean radiator too...nothing stuck (like grass, etc) in the honeycomb thingys or extremely beaten up by highway debris

 

Very abnormal, so needs urgent fix. Sorry to bear bad news. Try not to let it happen until it's fixed.

 

Called the guys I bought it from and they just had the coolant changed. It was about 8oz low this morning. Filled it, tapped the lines and got a few bubles. It was good for about 30 min on the highway but then the temp. gauge went up again. I called those guys back and they are going to pay for the therm. to be changed just in case. I hope it not something else more serious.

 

Check if it keeps losing coolant and if so hope it's somewhere easy to fix!

Be very wary of the V8 as it likely will warp the heads given a chance.

 

Check to see if there is coolant dripping just behind the LH front (driver's side) wheel after the engine has been shut off for a few minutes. If you see coolant dripping in that area, it's most likely a cracked overflow reservoir, which is a quite common fault. If that is not the case, try bleeding the cooling system to remove trapped air by following the JTIS procedure for your year and engine type.

If the previous owner is going to have the thermostat replaced, the system will be bled as part of the replacement procedure. Remember to check the coolant level after the vehicle has been driven and reached normal operating temperature.

NBCat

 

Sounds like it's possible the system wasn't properly bled after the coolant flush.

 

Does the OEM replacement coolant reservoir have a sturdier nipple?

 

No, it's the same.