Overheating Sebring
 

Hi Guys,
I own a Classic Roadster Sebring. It has had overheating problems since I bought it. It did have an old style giant fan that overheated at slow speeds when the engine revs were low and the weather was hot. A mechanic I know replaced the water pump and switched it over to an electronic fan. Now I have the opposite problem. It overheats at highway speeds. I thought about going to a different radiator or an aluminum radiator. It's a Ford 302 with an automatic.
Any ideas.
Also I'm a little north of Phila in Pa. If anybody knows of a mechanic in this area good with these cars I'd like to contact him. Really don't have the skills myself for major repairs.
Thanks for any input.
Glenn

Make sure that the radiator hose is not collapsing with increased water pump speed and shutting down the normal flow. Some hoses have a coiled spring inside them to prevent this from happening. See if it is easy to squeeze either of the hoses, particularly the bottom one, to the point where flow would be seriously affected. Obviously, don't do this when the engine is quite hot.

Glenn,

Have you joined the Yahoo Sebring Owner Group? Sebringowners : Sebring

Do you have a fan shroud on it?

Glenn,
how far is a little north?

email me,

Fred

Quakertown

is it drivable?

If it overheats at highway speeds and assuming there are no mechanical problems, the cooling system is under capacity. What radiator is installed?

It is drivable. It does have a shroud on the fan. The hoses have springs in them and I don't think they are collapsing. I think the radiator is the same crappy one these cars came with but I've only had the car about 1 1/2 years so I'm not sure. It's a 302 2 barrel.
Thanks for the suggestions.

Yumski,

Let's see if I am following you correctly.

1) Before the work was done it only over-heated going slow in traffic (city streets) and then when you would be driving faster (freeway speeds) it would cool down and not over-heat.

2) After the work was done it stays cool when going slow in traffic (city streets) and now over-heats when driving faster (freeway speeds).

3) You are still using the same radiator as before.

4) The only change was the water pump and electric fan with a shroud.

Did you have a fan shroud before the work was done?

Maybe a bad water pump? I know it is new but there have been bad ones before.

What size thermostat is in it? 160°-180°-190°?

Is the water pump spinning in the correct direction? There are normal and reverse direction water pumps. (should be ok because it is not over heating at slow speeds)

Is the fan turning in the correct direction? (again, should be ok because it is not over heating at slow speeds)

If it ran cool at higher speeds (freeway driving) before than one of the changes messed that up.


Edit:
In addition, If you are not a member of the Yahoo Sebring Group, you should join. Nothing like getting answers from people with the same exact car as yours.

Let's eliminate some mythology. The lower hose has a spring in it to keep it from collapsing because the radiator isn't passing enough flow thru the core. That can happen from size, or being old and corroded. It's a band aid by the hose makers to keep from being blamed when poor maintenance or selection is the cause. It's not their fault, just something they charge extra to keep it in the owners ballpark.

An engine fan for cooling purposes needs to have a 2500 cfm rating to cool the average motor at idle and stop and go. What rating is the fan that got installed? I suspect the first was inadequate. What is the flow rate on the electric pump? It's apparently not circulating enough coolant at speed, either the flow rate or quantity. It might not simply be burped out and completely filled.

All the work arounds are the problem to the simpler solution of using a more conventional fan, fan clutch and normal pump with a factory sized pulley on it. About all it will save is 6-10 hp, using the latest lubricants on the market does that.

There's a lot of "false horsepower" being marketed. It's significant to remember that products are sold because they can be, to make profit. The makers are under no obligation to say it might not be in your best interests. They aren't the engineer for our car, either, WE are. We're solely responsible for the selection and installation of what goes on it, make the most informed decisions you can.

I have a Sebring also, very similar configuration and heat problems. I am trying not to just throw money at the problem hoping for a fix. Are you saying that changing the fan speed by changing out the water pump pulley is a good first step? I thought about that but have never heard of anyone doing that to address the problem.

I did try the Amsoil cooling additive, mixed with water (no antifreeze) Saturday, and it looks like I've dropped about 10F. I also think that the Sebring would benefit from fender vents, as the air flow under the hood doesn't seem to be very good.

Terry could be onto something here... if the fan is rotating backwards, i.e. blowing out the front, it might cool fine at slow speeds where it has enough power to overcome the motion of the air being pushed at the radiator. Once you get up to speed, the fan might be working against the forced air, effectively making a dead zone for air-flow at the radiator. This would allow colling at low speeds and overheating at high speed.

It would be a simple fix, if it is wired backwards...

Good luck!

Make sure the radiator core is not or dirty or plugged.

Hi Guys,
I flushed the radiator and it seemed to flow pretty well. I'm going to look at the fan today to see if backwards rotation is a possibilty.