Few last issues with car temps

[FST FOX]

Little history, car sat for 3 years unprepped, when I got it I did alot to make it road worthy, flush all fluids and drained gas all the stuff you are suppose to do. Well a new thermastat, water pump go into it with a fresh mixture of coolant/water. Car runs and drives great put alot of miles on it today but one thing is when it sits intraffic or still for a while it crawls towards 100c but when driving it stays around 80c. Then no matter what when I shut the car off you can here the coolant boiling in the overflow/reservior. my guess is either I have a bad mixture or need to flush the system more or build up is in the radiator causing the rising temps when sitting still. Do ya'll think I am right or am I missing something

motor 347 stroker
check fan rotation, timing and fluid levels, and fan operation
another thing is I might change the temp sensors as they appear to have some corosion/build up on them

[Ron61]

Fox,

I don't know what your temperatures are there but when you are driving the car is going to get warmer in traffic and stop and go on the highway as the fan alone tries to pull air to cool it. As for the gurgling into the overflow tank, that is what it is there for is to save water. When you first shut the motor off, and especially after a hot day, you will get a huge temperature rise and it will force water out. The tank catches it and then as the engine cools pulls it back into the system. I put a little to much in my overflow tank other day and drove to Redding and back in 117 degree temperatures and when I shut the motor off, mine over filled the overflow tank and I had some water running down the driveway. I wish my Coupe had one of the cheap plastic ones instead of the high priced brushed aluminum one that I can't see into. That is where I add water in my other cars as they have a hot and cold level and it is easy to tell if you are over full or low.

Ron

[MaSnaka]

Is it possible you didn't purge all the air fron the system? Therefore giving you less capacity. Just a thought. Also comes to mind is the fan...is it shrouded to create good air flow over the radiator? It sounds like it could be the radiator is cloged but I would check the easier stuff first.
John

[wtm442]

Check the water level after each run. There is (was) probably some air pockets. Do not do anything radical until you have checked level after 3 or 4 extended drives. Been there .. done that.

[Tim Brewer]

Like Ron says, it is supposed to force water out when the radiator gets really hot. But if it does it too easily, you probably need a higher poundage cap on your radiator.

[FST FOX]

I might flush the system again, some good products have been suggested, but with what I saw on the water pump this might me the ket before pulling the radiator, fan is shrouded and working great but I will do the purging after I flush it today, should be taking a nice cruise tomorrow as well

[Dwight]

1st no more than 25% antifreeze, you live in Tx maybe a little less.

2nd do you have a filler just above your t-stat outlet? If so you should have the highest rated cap 18-20 lb there. The radiator should have a lower rated cap 16 lb. Your overflow tube should come off the radiator to the bottom of the over flow tank. From the top of the over flow tank you should have a tube to the lower part of the tank/car (for overflow). Maybe this picture will help.

3rd correct size/type radiator. A six cylinder radiator might not cool your 347.

4th do you have a adjustable fan control? is your fan large enough to cool you motor. Most fans are bought at Auto Zone and are not sized for the motor. Your 347 is bored .030" over and will run hotter than a stock motor. But with the pumbing hooked up correctly to the over flow, right size fan, correct anti-freeze mix and the correct radiator caps it will run cool!

Dwight

[FST FOX]

The radiator is self contained and I have onlt one car which is mounted on theoverflow canister that sits between the motor and radiator, cap is an 18lb (new) and like I said I will adjust the mixture and I will also use distilled water vs tap water. I am no stranger to 347 had one in my stang for years and never had hot issues, maybe I am thinking 100c is way to high which it only goes to 100c at stop lights or heavy traffic, it will run right around 87 when driving normal.

[Dwight]

100C is 212 F

at 100C it's a little hot but not bad. Does you gauge go above 100C? The water may be hotter than 212F.

We have had heat problems with 5.0 EFI motor, 408 Windsor, and a couple of FEs. On the 427 we found large pieces of power coat that had released from the inside of a 2" tube on the return hoses. They were tangled up in the wire coil inside the return hose. At low speeds they would close off part of the return and cause the motor to over heat. On the 5.0, 80% anti-freeze was the problem. 408, wrong caps and over flow tank plumbed wrong. Coach and I have had a couple of lessons on heat.

Dwight

[bobcowan]

boiling into the resevoir after shut off is often a symptom opf a blown head gasket. Check that before doing anything else.

Most radiator shops can test the coolant for hydrocarbons. it's inexpensive and quick, and will answer a lot of questions in a short period of time.