Not in a Ranger but looking for just some general info...

I've got a '68 Mustang with a 302 and I'm having a few issues with the cooling system.

Cruising around town it'll seem to sit at 190* all day long. On the highway, not so much! Most of the time it'll climb up to 220* but hasn't gone more than a couple of degrees above which makes me lean towards a flow issue.

Tonight I flushed the cooling system and tomorrow night I'm going to do it again. Then I plan on taking the thermostat housing off (and replacing the thermostat just because I have it off anyways) and pulling the water pump off to check the impeller. I also plan on pulling the rad out and turning it upside down and running the hose through it backwards just to get anything in the top tank out that's too big to flow through when I flushed it in the car.

In my shop at idle it didn't go any higher than 160* but I didn't rev it at all and there was no load on it whatsoever.

Just wondering if there's anything you guys can think of to check that I may be missing.

If this doesn't do it I think the next step is a new rad... either a stock replacement or aluminum upgrade as this thing is tiny! I may do a 5.0L FI swap at a later date so I'll want an upgrade anyways. I'm just trying to get it cooled down for the rest of the summer before I put it away and work on it over the winter.

 

Is it pulling enough air into the engine compartment?
I can't remember if thats a clutch fan or not. but you may not be getting enough air. If the flush doesn't work, try looking into a newer fan first.

 

It has a clutch fan. It seems to be pulling all kinds of air because it'll cool the car down from 220 down to 190 after coming off the highway which leads me to believe that it's some sort of flow issue.

 

I'd look for these:

dead impeller
collapsed lower hose
clogged radiator

 

Thanks Bob! Two out of the three I was planning on checking tonight. The lower hose seems good as it has a spring inside it.

 

You might as well check all three, once the radiator is drained and out it will be easy to check the impeller and of course the hoses will be off.

I have run a few 302 Stangs without any heating problems, What do the insides of your heads look like, may have a blockage.

Also, if the clutch fan goes bad it will lock up and cause the engine to run cool.

When you flushed the system, hat did the water look like after the flush ?

If all else fails… pull the intake, look in the water ports of the heads and see what is in there, might surprise you.

One last thought, have you changed anything on the outside of the front end of the vehicle ?
Sometimes a change in air flow can screw things up.

luck.

 

Thanks. I was planning on checking the pump and everything too. When I flushed it the water did come out pretty brown. I'm going to put another 10min flush in it again and see what happens and then take the hose to it to see if anything else comes out.

I haven't changed anything that would cause a blockage or airflow to the rad. If this stuff doesn't help then I'll pull the intake off and see what's going on there!

 

Start the car and put your hands on the radiator hoses, as it warms up, you'll know if it's flowing or not.

 

Prestone makes a kit i use all the time to flush cars.
I wouldn't recommend using a detergent. In older cars i've heard of it causing issues.
But the kit Prestone makes goes into the heater core hose, and you can run the car while its being flushed.
i've had good luck with it.

Also, Easy way to check for a broken impeller or water pump issue is to pull the hose off that comes out of the pump, and push water through the system. If it isn't coming out right, then you've got an issue.

 

It does get warm. I know it's flowing... it's just the amount of flow that I'm concerned about.

 

I've already used the detergent stuff so hopefully it's okay. I'll give that a shot checking the impeller too.

 

The rad is flushed and removed and it seems to be good. I don't know how to tell for sure but when I have the rad out and put a hose in the top it flows well out the bottom... if that means anything. lol

I'm going to replace the lower hose... it has a spring inside but the hose is older and the spring inside is much smaller than the ID of the hose. I don't think it's enough to restrict the flow but I may as well put a new one on while it's off.

I pulled the stat housing off and it's got a 160* in it. I'm going to swap it out too just because it's out. Tomorrow night I think I'm just going to pull the water pump off and check it out too.

If everything checks out there then I'll put it back together and hope for the best. If it still gets hot I think I'll just order an aluminum rad and see what that does!

 

So I put everything back together so I could drive it this weekend. After flushing the rad, putting a 180* stat in and cleaning everything else up it's running at 190* on the highway... so that dropped it 30 degrees!

I've already ordered a new rad as I know this one is at it's limit because it is a 6cyl rad. I'm just running straight water so I can just dump it, put the new rad in with the new hoses. None of the replacement hoses come with a spring in them so I found it separately when I ordered my rad. From what I've read it's only there because when they filled them from the factory they needed something to keep them from sucking in when they filled the rad using vacuum. For the $6 is costs I may as well throw one in anyway!

Here's the rad I ordered! It's supposed to support 400hp so it'll do me just fine. I plan on a few upgrades but nothing that will exceed that!

 

The big question is will it fit and have room for the front end of the motor/accessories ?

Also, aluminum... May or may not be better than a brass radiator but something to thing on, cooling of the aluminum is something to take int consideration, electric fan running after engine is turned off.

There are radiators out there for the conversions and they cool well enough.

 

Most Radiators are Aluminum now days. The one in your truck is.
My Grand National's Rad is Aluminum, and that car hasn't gotten hotter than 185 degrees since i put its new one in.

 

Yes, it'll fit. It's listed for the same year as my car for car converted to newer SBF's with the driver's side lower hose.

At this time I'm not going with an electric fan. I may later on but for now the clutch fan seems to be doing the job just fine!

 

Guess I never updated this... the rad is in and all seems to be well. Took some time to find a lower hose that would fit though as the outlet was about 2 inches farther toward the center of the car compared to my old one. The trans cooler inlet/outlet was the same way, but I just had to make two new steel lines for them.

The car is now running at 180* and as soon as the rad was all done my heater core started leaking. lol I love old cars!

 

Sounds like the old radiator cap was weak keeping the system pressure low.

The new cap bumped the pressure and poof you get a leak.

I would replace hoses while your changing the coolant again.

 

I'm thinking flushing the crap out of it probably made it leak. I ran it for a while with a new cap but that could have had something to do with it as well! I just replaced the hoses so I should be good to go there.