running hot

M

maxandmickey

Member
hello everyone,need some expert advice.would a small leak in the exaust cause a engine 1930 model a to run hotter than usual? what are some symptoms of overheating.will the coolent start to boil and steam right away.i seam to be hearing a small pop when I am driving it.just when I rev it when shifting.coming from exaust manifold and muffler.clamp seems to be a little loose.thanks everyone
 
If you have coolant in the exhaust port, that is bad. They are prone to cracking between the ex. valve and the cylinder. Take off the manifold and take a look. If it is just popping when downshifting check the condenser. Also, let the engine idle and look in the radiator and look for bubbles. Are you losing coolant?

Mike
 
If a leaky exhaust made a car overheat, then my Town Sedan would always run hot. I cannot seem to fix my exhaust leak permanently. I redo it and it is great and then after 50 miles or so, it leaks again. A leak in the exhaust pipe will lead to backfiring, as I have proven many times over the years.

I have a motometer that gives me an idea of what is going on. The best thing to do is to read the radiator with an infrared gun after you get the car warmed up. My 30 Town Sedan runs at 140-150 degrees or less and my 28 roadster runs at 180-200, which is too warm. There are many threads on here about cars running hot and why.
 
Last edited:
maxandmicky,

You need to differentiate between an exhaust leak and running hot. I would do a quick test to see if you have a blown head gasket putting combustion chamber exhaust gasses into the coolant. Take the fan belt off... and fill the radiator to the top, start the engine and see if you're getting any bubbles at the radiator neck. Don't mistake rippling for bubbles. If not, that's a good sign. If it is blowing out bubbles and pushing the water out you have a probably head gasket issue. if no bubbles lower back down your coolant level and re-install belt. You may have a radiator issue

Exahaust leak
If you have an exhaust leak at the manifold to pipe, I would recommend when cool lowing the clamp and pipe. clean both mating surfaces well. Using a small floor jack with very little pressure ( just enough to get it there) use the jack under the pipe near the bend to put upward pressure on it so it meats the manifold flange. Take a small ballpen hammer and shape and peen the muffler flange to the manifold. Make sure the pipe is square on the mating flange. Sometimes the pipes need a little torque or movement to get it there. Once the flange is shaped to the manifold, you can then lower a little, use a sparingly amount of muffler cement between the two surfaces and using the jack put a light pressure on it back up while replacing the clamp.
tighten well and ensure alignment is good from the side and front.

You may also need to replace the manifold to block gasket and resurface the manifold if it is leaking there. Snug those bolts tight but not hulked 34 lbs is fine.

While you're at it check your carb to intake bolts to make sure they are tight as well.
All the above is all too common on them. Best of Luck!
Larry Shepard
 
Spend some time and search thru the forums and acquaint yourself with some of the problems other have experienced and their solutions. Owning and driving a Model A requires more background info than a modern car.

As you your question a leak around the manifold or around the muffler IMO would not by itself cause your motor to overheat
 
I had a similar issue after i put the new engine in my car. Constantly overheating. Thought it was the exhaust leak. Got a new manifold gasket, didnt fix the problem. Then reset my timing, didnt fix it. Then changed the distributor, still didnt fix up. Wound up being the tubes on my radiator were jammed up. Replaced the radiator and no more overheating.
 
Any exhaust leak will cause popping at gear shifts and when letting off the gas but won't cause over heating. Retarded timing or over retarding the spark lever when driving will cause over heating and even more popping when decellerating. First check points gap. as the rubbing block on the points wear the points gap closes. When the points gap decreases the timing becomes more and more retarded. Factory specs for points gap is anywhere from .018 to .022. I usually like to run the wider points gap, this gives more time before the points will need to be readjusted. I usually run with full advance at speed but you have to be carefull not to strain and lug the engine with a lot of advance in high gear. In other words, keep your momentum built up for hills and don't strain the engine. Retarded spark and timing is a major cause of overheating and loss of pep and power.
 
If I understand you correctly you have a leak in the exhaust system and the car over heats.
The short answer is No, a exhaust leak will not cause the engine to run hot.
These two are usually not related. You could run without any exhaust system and it would not make the engine run hot, but a clogged exhaust system could make the engine run hot. If you are getting fresh air into the exhaust system you will have all the elements (fuel, heat, and oxygen) to cause the small explosions you hear as pops. Sealing the manifold to
exhaust pipe connection is usually the answer.

First the exhaust system: the system consists of a few parts and connections and there is a different way to fix all of them, so please explain where exactly it is leaking and we could go from there.

The overheating: most of the time you will find it is a radiator problem and will need a flushing or professional help. There is a lot of discussion on ford barn about what and how to figure out if it is a radiator problem.
There is a bunch of reasons for running hot but knowing the radiator is not the problem will help you find any other problem that might also be adding to the temp problem.
 
Last edited:
You must log in or register to reply here.
Back
Top