New Oil and Temperature Question

[RedByrd]

Hello to you all,

As the proud owner of a 95 Ford T'Bird LX with the 4.6L engine, I recently was experiencing some problems with overheating.

I checked my oil at the gas station as normal, and noticed that I was running a bit low (close to the add mark). Since I was only about a week from an oil change, I decided not to top off. During that week, I noticed that my car ran hot often. The cooling fan came on even at short stoplights, in slow driving areas, etc. which isn't normal for that car. I understand that oil plays a role in cooling the engine but I honestly thought I had a cooling system problem.

The other day I changed my oil, replacing conventional Castrol GTX with Motorcraft SynBlend. Since then, my car hasn't reached "normal" on the temperature gauge. Even on long trips (20+ miles highway) the temperature stays slightly cool. The operation of the heater isn't affected at all.

I don't think that this is a problem, I am just curious. Does the properties of the types and brands of oil differ so greatly that it affects the engines operating temperature? Is this normal or is it something I should be keeping a close eye on.

Thanks! I trust the people here to give the straight answer

 

[Jim 5]

Welcome!

I doubt if your engine temperature issue relates to your choice of oil if the grades are even close to one another.

I would look into your cooling system and find the source of the overheating before it strands you somewhere far away from home. Keep us posted as to what you find out.

 

[hate2work]

I'd have to say no, your choice of oil isn't related to your overheating.

Curious though that changing the oil had that effect on the temp.

How is your engine coolant? Level OK, good condition, etc?

 

[RedByrd]

Coolant is fine. Has some age to it, but is at the proper level, showing no signs of rust or contaminants, and was tested to be good to -25 degrees... it rarely gets to 25 plus here!

It is due to be flushed here at the next oil change, though.

 

[edhackett]

Let's see... overheating, then not getting up to "normal" temperature. Failed thermostat.

Ed

 

[hate2work]

Originally Posted By: edhackett
Let's see... overheating, then not getting up to "normal" temperature. Failed thermostat.

Ed


You forgot "changed the oil, then it worked normally."

That's the weird part.

 

[c3po]

Originally Posted By: RedByrd
Coolant is fine. Has some age to it, but is at the proper level, showing no signs of rust or contaminants, and was tested to be good to -25 degrees... it rarely gets to 25 plus here!

It is due to be flushed here at the next oil change, though.


How long has the coolant been in there.

 

[RedByrd]

Coolant has been in slightly over a year. This car doesn't "use" coolant and the book gives a long change interval - don't recall it off of my head though. I shoot for a nice change/flush every three OCI's or about 15,000 miles (where I live, it neither gets particularly hot or cold).

 

[c3po]

Coolant should be o.k., how long has the thermostat been in there.

 

[mcrn]

Possible faulty gauge?

 

[chevrofreak]

Was the GTX by chance a thicker oil than the Motorcraft?

 

[Jim 5]

Originally Posted By: hate2work
Originally Posted By: edhackett
Let's see... overheating, then not getting up to "normal" temperature. Failed thermostat.

Ed


You forgot "changed the oil, then it worked normally."

That's the weird part.


I think this is a spurious correlation (coincidence).

 

[RedByrd]

As much as I hate to admit it, the thermostat may be original. I don't have any service record to indicate that it was replaced.

Both the Castrol and Motorcraft are/were 5w30, the difference being the Castrol was conventional and the Motorcraft is a synthetic blend. Even though my engine is clean, perhaps the different oil somehow loosened some deposits that resulted in higher temperatures? (Just guessing).

 

[demarpaint]

I'm thinking coincidence and a bad thermostat. I would replace the thermostat, especially if you think its the original.

Frank D

 

[mechtech2]

If anomalies persist, dig deeper.
Right now, leave it alone and keep an eye on it.