I have an unusual problem for an XJS...

It seems that my engine does not come up to temperature!

It's been no warmer than 30F here in the DC area and my needle stays left of the N, closer to C.

I checked the temp of the coolant with an IR gun as well as taking readings from the OBD port... 168F

168F!

Is that too cool? I'm asking others who are experiencing cold weather to see how your 4.0 is running.

 

What thermostat do you have? Whatever the thermostat rating is the coolant should stay *at least* that hot.

I suspect your thermpstat is stuck open

Cheers
DD

 

second on the stat being stuck open! It is cold enough that if it is partially open it doesn't overheat but wide enough to cool the engine when it doesn't need to be cooled, causing it to take waaaaay longer to get up to temp.

 

I ordered a Wahler thermostat, which comes with the O-ring gasket. I've also ordered the gasket on the other end.

I suppose I'll have to drain some of the coolant out.

What's the best way to do this?

 

I have done it several times because I am always paranoid about thermostats sticking. Never drained the radiator, just do it fast with the engine cool and a large pan underneath, then refill the reservoir tank.

 

Yeah you have to pull both hoses anyway, and the only other way to drain it is to pull the main lower hose, so just get a catch pan and let it drain when you pull the hose from the stat housing. Like spike said, ends up draining less coolant anyway