I recently had a thread about my temp sensor being wacked. I replaced the sensor and my temp guage still doesn't read right. I got one of those Mr. Gasket radiator caps with a temp guage and my truck usually sits at 140 while running. But I just cant understand why my temp guage is still not reading normal. It stays near cold.

I also changed my oil this past Sunday. I used Ford Motorcraft oil (10w-40) and now I have a very slight noise in the bottom end. I used Pennzoil (same weight) and never had this issue. Motorcraft oil no good or good?

I like to use OEM equipment for my vehicles, most of the time. Like with my Dodge, I stick with a Mopar filter and M1 full synthetic oil. I went to Advance Auto and they had Motorcraft oil.

Thanks.

 

That's because 140 IS cold. Your truck should be running between 195 and 205. Sounds like your thermostat is stuck open. Give the cooling system a flush while you're at it - that's why the t-stat rusted in the open position.

Motorcraft is good oil. I use Mobil-1, as I think it's the best oil you can buy, but there are many other good oils to use as well. Two that I would never use are Pennzoil and Quaker state. I don't know if it's the case anymore, but they used to contain large amounts of wax, which would build up in the engine and eventually cause it to fail.

I use motorcraft filters. There are too many cheap filters out there - never use a fram filter.

 

I bet you replaced the sensor on the thermostat housing right? If so that one is for the computer and does not affect the dash gauge. The dash is fed from another sensor near the front drivers side in the lower intake, it has a single wire attached over a stud in the top.

 

I located the sensor on the lower manifold and its the same type of temp sensor I replace in front of the engine. Also, its actually 2 wires instead of one you guys have been mentioning about. I have gotten a new t-stat and will be doing a flush and replacing the t-stat this weekend.

I still like to hear about the Motorcraft oil and why the bottom end sounds like a small diesel. Its not real bad, you can barely hear it. Like I said in the original post, I never had this problem with Pennzoil.

 

The two wire sensor in the driver side lower intake manifold is the air temperature sensor. The water temperature sender is more towards the front of the engine from the air temp sensor, and has one wire.

Is the Motorcraft oil a synthetic blend?

 

You never did say what brand filter you were using. What brand?
How many miles on the engine?

 

That is the wrong one, it has one wire.

 

The Motorcraft oil that I bought wasn't synthetic. It just said Motorcraft Premium Oil. I guess that means synthetic in Ford language?

The engine has 71k and i'm using a Motorcraft oil filter.

Anyway, got to go back cutting grass.

 

Well, I honestly will never use Motorcraft oil again as I just developed a very small rod knock at the very back of the motor. Very unhappy as the motor always ran quiet even with dirty oil! Argh!!!