200 ci Overheating....Help Please !?!

[Anonymous]

Hi - I'm a newbie to the world of sixes. Don't hate me because all of my previous 65/66 mustangs have been 289s.

Currently, I have a '66 Sprint coupe that I've restored as a driver. I really like the nimble handling (feels like a V8 car with power steering!). But now that it's ready to drive I'm having bigtime overheating problems. When I got the car it had been sitting up a while, so I replaced the radiator with a new standard sized one, along with a Gano filter (it's not clogged) in new hoses. Since then I've cleaned and flushed the system (although not a power flush), tested and replaced the thermostat (180 degree), and just replaced the water pump.

It's still overheating. :x

It's been suggested that it's bad timing caused by a worn out or maladjusted distributor, and that I should replace that. It's been suggested that I remove the thermostat, which I've always heard was very wrong. Another guys says the engine must have serious head problems.....Could be all three, eh?

I've never had this sort of a logjam with my 289s, so help a brother out here who's trying to keep his cool about an overheating sixer.....

Any suggestions? Thanks - Dickson

 

[Anonymous]

Dickson,
First, do a search on overheating on this site. This has been discussed many, many times and there will be a lot of good information in those threads. I have had many problems with this myself, so here are my suggestions.

1) Check that thermostat!!! Sometimes new ones are not working, and they frequently go bad. Some guys test thermostats on the stovetop in hot water...Your new one could be bad. I wouldn't remove the thermostat completely, but would check yours.

2) The radiators in our sixes are oftentimes undersized. You can upgrade to a three or four row radiator which will increase cooling capacity.

3) What is going on with your water pump? It could be bad, which is not uncommon, or to hard of a fix. It might be worth pulling that pump and having a look when you replace the thermostat.

4) Timing can be a real issue. I don't know if your distributor is worn out...but you want to check that your points and rotor are good. It will help to have your timing right, so make sure you time it.

5) Coolant....make sure your coolant is the proper mixture of coolant and water. A 50/50 mix is usually pretty good.

6) Fan....many guys upgrad to a flex fan that will produce more air flow through your radiator. There is no real down side to this other then it won't look original. Also, people tell me that a fan shroud will improve cooling a lot, but I have not put one on my car yet...but I want to do so.

7) Head....If you are not losing coolant, or oil I don't know if you are going to have a major head issue. You might have a blown head gasket, but that can be changed pretty easily. These engines seem to blow head gaskets from time to time....others will know much more abouth this then I do.

8) Look around your engine and take some time to think of anything that is involved in the cooling system to make sure it is working. After many misdiagnosed overheating issues...it turned out that my car had a leaking freeze plug on the back side of the engine that only lost coolant when the car was being driven. I found it when I pulled the engine to put in a rebuilt.

Hope that helps a bit. I am a novice. There are guys here who can give you a lot more support. Good luck, let us know what you find.

Ryan

 

[CobraSix]

SOunds like you've hit most of the major things. Here is a question, when does the engine overheat? What speeds? idle, 35MPH, 55MPH? Just curious. It'll help us narrow it down.

Okay...sounds like the only thing it could still be is the hoses. Maybe the bottom hose is shot (no spring in it) and is collapsing and restricting flow.

But timing will definitely cause overheating. I once had my timing retarded by like 10* ATDC, and after a 20 mile drive, the manifold was glowing red. I didn't realize the timing was that far off since I didn't have a timing light where I picked up the car.

Slade

 

[Anonymous]

Thanks for the replies.

I've checked the thermostat - It's opening fine and is new.

I'm now also wondering if it's the radiator cap - old original style - could be bad? I should get a new 13-15 lb cap, and fluid recovery bottle?

I'll have some time this weekend, so I think I'll replace the cap, and add a coolant recovery bottle and perhaps a new distributor. I've never done that, so with me luck....

BTW, the hoses are new, but the lower one does not have any wire reinforcement to it.....Can I bend some myself, or do I need to return this one for a reinforced one?

Also, it seems that the coolant gets hot quickly at idle (observed when I burped the system) but really it's overheating at normal cruise speed (20-35 mph - no highway).

Now I'm wondering if I should just break down and change the head gasket too.....How hard is that on sixers ? I've only done 289s before...Thanks guys.

 

[Anonymous]

Yes, go for the cap...that could be bad. I forgot to put that in there. Good Luck!

 

[CobraSix]

sounds like you've done the entire cooling system. My guess is your timing.

ANother question, have you verified temperatures with a mechanical gauge? Don't go by the gauge in the instrument panel.

Slade

 

[Anonymous]

While the mechanical/dash gauge is working, I don't need to trust it as after a while the car starts to smoke etc....It's definitely overheating. Stranded me on saturday.

I'm leaving the office - it's too pretty outside. Next stop Advanced Auto for a new rad cap, coolant recovery bottle, and to order a rebuilt distributor.....I'll just work through this component by component. I'm learning....and I'd really like to avoid pulling the head (just repainted the engine!)

 

[Anonymous]

Given that you have a new radiator, it is likely to be a timing issue. If you have the original distributor, it is likely that the vacuum cannister is leaking, and if that is the case, you are not getting any timing advance. The '66 only has vacuum advance. Get a distributor for a 68 instead of a '66. It has both the vacuum and centrifugal advance.

 

[CobraSix]

Another possibility.

how's the condition of your carb? Do you have any vacuum leaks? If you carb is running lean, you can overheat your car too.

Slade

 

[MustangSix]

I second the distributor check. The Load-o-matic only has a vacuum advance. If the diaphragm goes bad or the line leaks, no advance, engine overheats while driving.

 

[Anonymous]

Slade - I had a vacuum leak on the carb, but thought I'd repaired that.....I have another 1100 I can pop on there easily enough.....Thanks for the suggestion!

 

[xzerokidx]

well if your gonna change the dizzy, why not put in a DSII distributer?

 

[MercuryMarc]

I had an overheating problem that went away after I replaced the radiator (aluminum 2 row racing unit), installed a tranny cooler, electric fan with temp switch, and new thermostat. But also I had a bad master cylinder that would not completely allow full pedal return (bad check valve?) and my brakes would stick after many pedal depessions, and would unstick after a few hours. I found this out after all the cooling work was completed.

Needless to say, I belive a large part of my "cooling problem" was actually a brake problem...

Live and learn....

But I have really great cooling set up and there is NO WAY this baby is going overheat at Hot August Nights again.....

Marc in SF
63 Comet with w/200 ci
My New Rad:
http://www.angelfire.com/falcon/comet0/rad.html

 

[TheDude]

Hey Dickson,

Welcome to the Ford Six forums.

A blown headgasket would allow oil and coolant to leak out so it should be easy to figure out if it is a blown head gasket or not.

 

[Anonymous]

Well I got everything done today that I wanted to do - replaced the carb and distributor with new ones, and installed a radiator overflow tank.

I won't bore you with the details, but all in all everything went pretty well and I am proud to have accomplished it all in a morning. Amazing to me that the car actually fired on the first try after all of that......

However, it's still running hot and I don't know why. My carb spacer's shot, so I'll get another.

Also, I'm going to break down and buy a high capacity radiator. I want to solve this problem! :!: Dickson

 

[CobraSix]

unfortunately, most cooling issues are that way...very illusive. I ended up replacing my entire cooling system before I finally fixed mine. just look to your timing as well. a stock radiator and fan should be able to keep the car from overheating if the cooling system is done right.

Slade

 

[Anonymous]

Dickson;
Don't neglect the ignition static timing test. If you have less than 6 degrees advance or more than 12 degrees advance at idle (assuming a stock cam), it will run hotter than normal. Also, if you have points, too small of a points gap will make timing run late (like 4 degrees advance instead of the desired 6-8 degrees). You can check this with a dwell meter or feeler gauge.
A vacuum leak under the carb can also cause heating, as can a leak where the manifold vacuum port(s) are, near the carb, on the intake manifold (the "log"). These manifold vacuum adapters often work loose, then leak. If the car has been sitting a long time, the hoses or vacuum caps on this manifold vacuum adapter might be rotted off, too, causing leaks. This leaking causes heating, too.
Radiator fan issues: make sure the fan belt is tight. If you have the clutched fan (rare), make sure the fan engages when the clutch is hot (it just has more 'drag', as felt by hand, when hot, and freewheels when cold). Make sure you have the radiator fan shroud in place: lots of owners remove these if they start to break up from age. This reduces fan flow by almost 50% if the shroud is gone!
Mine is a late 1970-series engine, but the radiator cap is 16 lbs.
The 180 thermostat should be perfect: don't run without one in place.

Hope these help.

 

[Anonymous]

Ya know I had the same exact problem you are having. I went though all the steps, head gasket etc. I replaced the thermostate etc. I finally had done everything, and in a last ditch attempt i removed the thermostat. It didnt over heat!!! Low and behold even though i had put about six different thermostats in there that was my problem. I had tested every one prior to the install and all worked fine but once in the car they ceased to work.

I dont know how savy you are when it comes to thermostats so ill play dumb..

Your thermostat has to be put in a certain way. If you dont put it facing the correct way you have destroyed your thermostat and usually your housing too.

You might end up going through quite a few of them, i think my toatal was around six before i finally found a good one.

 

[Lazy JW]

Indeed, one of the old wive's tales that refuses to die is the one about removing the thermostat and having that cause overheating because of the water flowing through the system too fast. Having been born on the wrong side of the tracks, I have had opportunity over the years to drive numerous old junkers on farms and on the highways. Most of these vehicles had little or no maintenance done on them, and that usually means clogged up cooling systems. I have personally removed or seen removed quite a few thermostats on overheated farm trucks and some cars, and without fail, EVERY one of them ran cooler. Now, I don't recommend this as a proper fix for lousy maintenance, but it will get you home if you get caught out on the road, and it is well worth investigating, as I have had bad thermostats out of the box too.
Joe

 

[66Sprint6]

I was in the same boat man, checked everything, replaced the fan and put in a new mech. gauge. When I put the gauge sensor in, i notice muddy coolant. Ends up my water pump was bad, now it runs cold, it amazing!!!! I got a quick question, what temp should I have the fan turn on. I warmed up the car the other day and I got scared quick... The gauge only said 160* but when I went to adjust the fan to come on it was HOT in that engine bay. I guess it just spooked me but what do0 yall say is a good temp to go for?
Matt