Temp guage pinned at High

[freeulster]

I just bought my Expy a week ago. It is a 98 XLT 4x4 with the 4.6L engine. My temp guage pins itself to high with key on. I changed the temp sensor on the passenger side front. Still pins to high. when the pigtale is disconnected it still pins to high. Any ideas? No check engine light and no codes(i have an obd2 reader). This was a common prob with my 91 explorer and a sensor change would fix it. I forgot to add that I have no heat, always blows cold. I do have coolant in the reservoir bottle and the level changes.

 

[freeulster]

OK I really want to fix this. Is this the right forum? Is there enough activity here to get any kind of help? I really don't want to burn up my truck! Start the cricket symphony.

 

[LeeLeadingham]

Best thing to do, is get a mechanical gauge, and see what temp your engine really is running. You probably just have a bad gauge, but I would check and make sure first.

If you don't know how to do that, most shops can and will tell you how to do it.

Goodluck, hope you get it fixed.

 

[cekkk]

Wow, 3 months for a reply. I joined today and asked an electrical question. We'll see what happens. On your problem, prior poster had it right. I would not put much faith in stock gauges no matter what their readings are. For instance, on my F350 powerstroke the stock transmission gauge goes to full operating temp in a mile, less if it's warm. My ISSPRO gauge is probably still bottomed out. It will go from about 140 - 160 and if towing up a mountain on a hot day, maybe a tad over 200. The stock gauge? It hasn't moved since five minutes after I started the engine. If you're not getting any heat I wonder if these Expeditions have a bypass valve, my 350 does so water doesn't flow through the heater when ac is on max. I don't know if DW's Expedition has this feature or not, but others should know. If so, it could be stuck closed. I'd say that's your bigger problem, unless you live in a Phoenix like climate. Good luck.