Check Engine Light

[JackMac]

bbyer - thanks for the links, they are very helpful.

This looks to be a very common issue. Owners may consider proactively replacing. If the thermostat gets stuck in the closed position (rare, but possible) it could cause a blown head gasket.

 

[bbyer]

Replaced the coolant as well.

Yes, I replaced the thermostat and coolant when I did the spark plugs at about 90,000 km, (56,000 miles).

Re the coolant, it was more of a time thing, (five years), than distance as at some point in time, the coolant becomes a corrosion accelerator rather than inhibitor - and yes, the coolant is some special new sort as the Jag engine in your 3 is not made of the same cast iron as a Ford Flat Head V8 or the Chev Stove Bolt Six of earlier days.

I do not wish to learn how to change heater cores, front and rear, and changing the thermostat is less of a fuss when the coolant has been drained.

I might add that I have a ScanGauge II and it works well to watch what the thermostat is doing as the water temperature readout when set of F pretty much tells you what the thermostat is doing, or not doing.

 

[Rogo]

Re the coolant, it was more of a time thing, (five years), than distance as at some point in time, the coolant becomes a corrosion accelerator rather than inhibitor - and yes, the coolant is some special new sort as the Jag engine in your 3 is not made of the same cast iron as a Ford Flat Head V8 or the Chev Stove Bolt Six of earlier days.

I think the coolant is good ole DexCool. My dealer said it is the same stuff that's in the Disco 2.

How did you drain it? I haven't looked to see if there are drain plugs or lower hoses in a convenient location.

 

[bbyer]

Lower hose going into bottom of the rad.

Below is a link to the Australian site and a discussion re the coolant. The generally agreement is that it is either the red or orange coloured stuff. I think it is the Dex Cool but that is a GM trade name. The Chevron Texaco Havoline Extended Life Anti-Freeze Coolant meets GM 6277M which is Dex Cool.

http://www.aulro.com/afvb/d3-d4-rrs/132257-coolant-d3-v8-what-type-used.html

To drain on the V8, per the cooling system hose file in the link below, you pull off the hose at the bottom of the rad - not very sophisticated and not very convenient. Also, given the number of hoses, I am not so certain that they all drain. That is why you have to open the vent on the small upper hose and even then, it will not drain the rear heater and the like.

http://www.disco3.co.uk/gallery/thumbnails.php?album=3801

These are interesting links re DEX-COOL.

http://en.wikipedia.org/wiki/Antifreeze

http://www.imcool.com/articles/antifreeze-coolant/dexcool-macs2001.php