Hard starting and frothing coolant???

[paulbone]

Hello all,

Please help if you can, I have a couple of problems with the D24 coupe.

From cold she will start right up, with first press of the starter, but after that its a real pig to re-start. Even after 1 or 2 minutes, with the choke on or off, its hit and miss whether the car will start or not - I normally end up with a flat battery. If I go back to car after a 10 minutes or so she starts right up again - the symptons of vapor lock, but I dont think it is.

The automatic choke works fine, and the heat riser seems to work. I dont think its a vapor lock issue as it doesn't matter how hot or cold the engine block gets, still the same probelm.

One thing I did notice though, when I was taking the carb off to rebuild it (tomorrows job), is that the inlet manifold and the base of the carb were as hot as hell. Is this a clue do you think.

The other issue that might be related is that, whilst the engine is running with the choke on, coolant throths through the radiator cap and out of the overflow pipe. When the choke comes off, this settles down to a gentle stream rather than a raging torrent.

Coolant is getting round the block, as it was coming out of one of the freeze plugs. There is no sign of contamination in the oil though.

Again just so close to getting the car on the road after 44 years of sitting in a barn, and then we have these two issues.

Oh the temp gauge is stuck, so that doesn't help.

Thanks for any advice out there

Paul

[Norm's Coupe]

Hard starting when warm usually points to a weak coil. However, since you are overflowing at the radiator cap, it could also be a blown head gasket. A blown head gasket will cause hard starting due to lack of compression. If the head gasket blows on the exhaust side, the water will not go into the oil and vice versa. It will go out the tail pipe and of course cause overheating and the overflow problem. You should run a compression check to check out the gasket.

[1just4don]

Yes, sounds alot like blown head gasket. It starts fine when cold cause the heat hasnt expanded where it goes yet. ANY heat expands where it is going and makes it that much worse. Also thats about the only way for the radiator to be running over too. Its full of water(okay coolant) and when you add air it is over full. Take the radiator cap off,,,maybe,,, and watch if you have alot of air bubbles coming up there. You may want to check to be double sure your head isnt warped IF you have to remove to redo gasket. I dont know the history of it,,,could it 'ever' have been overheated where the head could 'warp' or the gasket may have died of old age. May you have better days ahead!!!

[JerseyHarold]

Have you done a pressure test of the cooling system? That will confirm whether or not your cooling system is intact. Also, a stuck heat riser or plugged exhaust can add to overheating problems.

[Don Coatney]

Have you done a pressure test of the cooling system? That will confirm whether or not your cooling system is intact. Also, a stuck heat riser or plugged exhaust can add to overheating problems.

D-24's did not have a closed cooling system. It is hard to pressure test a vented system. And if you do plug the vent and add pressure most likely the radiator tanks will balloon and self destruct.

[randroid]

Don,

I have been running a 4# cap on my stock P-15 radiator since the first time I boiled it dry at an elevation where water melts at 192 F, and my system has never had any problem with it. It is the same system used when Plymouth went to a pressurized radiator cap and there is nothing mysterious about it. I use a Stant cap with a seal that extends below the overflow tube and I bought it from NAPA so long ago that I'll probably replace it with a new one just like it when I fire the beast this coming Spring. There are other members of this forum who have done the same thing. I admit it was an experiment when I first tried it but had a spare radiator and was willing to take the gamble; that spare radiator still hangs in my garage.

A pressure test on a sound engine system will leak only at a 0# radiator cap and if any cap pressurized anywhere above ambient is used the test would be valid.

I've been asked several times on this forum to justify why I think I can incorporate pressure into our system, and the last answer I shall give is that I do it because I have done it and it works very well.

-Randy

[1just4don]

Randy,

You said to the point where water melts--192*. Did you mean water "BOILS"??? around here water 'melts' at 32*. If it took 192 to melt 'here' we would be in our next ice age!!! Maybe elevation makes the melting point different,,,it sure makes me uncomfy,,cause I am NOT used to it!! And I seem to boil at a lower degree every year,,,or is that called old age?? :D --d--