Weird cooling system behaviour

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D

DQ81

'73 Dart
Joined
Nov 12, 2008
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The Netherlands (Holland)
My 318 takes too long to heat up, in fact just gets over the first line around 120F, I've only seen it get up to operating temp once. It should get there quickly, I'm mostly driving around town.

However if it gets in between where it 'should' be it starts to steam out of the overflow hose off the rad (I don't have a reservoir)

I have a manually operated electrical fan but if I leave it on all the time temp NEVER gets above 120F

Cold motor is no good. Methinks open thermostat, but what gives with overheating behaviour at normal operating temp?

Also heater vents give warm air on the ride too, and cold air on the ride back or vice versa, it's random.

I've only had the car a few weeks and have put about 6 quarts of coolant in myself, alot of which leaked out or steemed of it seems, always comes out brown and dirty either way.

Clogged system? Too much water in the system perhaps from PO? Thermostat definately stuck open right?

Advise coolant flush and thermostat replacement? Am I on the right track or overlooking something?

If so how quickly should a 318 get up to operating temp (outside temp 40F) at idle with a 180F thermostat?

How many quarts to flush the system and what's the best way to flush the whole thing properly including heater core?

David
 
The first thing you do is install a manual temp guage to get real readings.Second test the thermostat and rad cap.You could have a clogged block and no coolant flow around the cylinders.Check the tune up and compression.If the motor is not making any power,getting heat build up is very hard.The water pump should be checked to see if the impellar is not spinning on the shaft,and moving the water.A big time flush or removal of the frost plugs could be in order to flush the block and new ones installed.What is the anti-freeze/water ratio you have,if its not 50/50,it takes much more time to heat up.Is the carb tuned correctly and the timing,You need to pressure test the system for leaks and if none are found,you have a internal leak,head gasket/intake gasket leak,mrmopartech
 
I would take the radiator hose loose on top of the thermostat housing on the motor, look down in the housing and see if there is a thermostat. If there is one shine a light down in there and see if it is stuck open. If isn't one a 180* or 195* would be good enough.

Drain the radiator first then take the hose loose. After you're done make sure you have a 50/50 mix of coolant and water. Fill the radiator until the you have covered the radiator core about a 1" or so. Crank the car and let run without the radiator cap on until the thermostat opens and you see the water/coolant go down. Add until it water/coolant is fairly close to the top of the radiator. Try to see that you have flow while you are doing this. This baiscally the way I feel my system. It does not check things such as the raidiator cap and so forth.

I always dill a 1/16" hole in the thermostat to allow air to escape.
 
Definitely put a mechanical temp gauge in there. The stock gauge could be reading incorrectly. New 13lb cap, new 180* milodon/mr gasket thermostat and pressure test the system as well. All good advice form previous posters.
 
Thanks guys. Will do as advised and let you know what happens.

As far as I can tell I have flow, in the radiator at least as the flow is visible with the cap off and engine running.
 
DQ81 said:
Thanks guys. Will do as advised and let you know what happens.

As far as I can tell I have flow, in the radiator at least as the flow is visible with the cap off and engine running.
Click to expand...

That's good to know.

Do you have a overflow bottle.... a small hose connected to the top of the radiator going to a "bottle"

This might be a good time to bring this up:

My does not have one... it just spits it on the ground. I know that this not allowed on the drag strips. I had a 68 Charger a while back that didn't have one either. I bought a overflow bottle from Summit racing and flipped the bottle upside down so that the hose would be on the bottom of the bottle. It worked really good and there was always some coolant in the bottle but never noticed if there was more or less. My thinking was it would serve like the modern day "catch canisters". If the radiator cap opened it would push the coolant into the bottle and then suck it back out if needed. Does this sound like right?
 
I just happen to have a 73 swinger overflow bottle.Interested??

73 dart special 019.jpg
 
pettybludart said:
I just happen to have a 73 swinger overflow bottle.Interested??
Click to expand...

Willing to ship overseas?!

PM with a price if so... mine just spits on the floor also, a hose comes of a spout to the side of the rad cap...makes me wonder how it stays pressurised then?

I've yet to get a Tstat as the only US car supplier in town is closed for the holidays :(

Otherwise I think I have an old GM (sacralidge!!!!) overflow canister lying around and for now, I'll mount that to catch the overflow...
 
ted_sweet said:
SOUNDS like factory guage is wrong
Click to expand...

I'll be installing an aftermarket gauge as soon as my local parts place opens and I can pick one up to see. Although I suspect it's a combinatin of a bad radiator, bad thermostat and leaky heater core.

I found a leak that sprays a mist of coolant out of the rad once warm under pressure today after I discovered rad fluid on my front bumper.

Than while mounting a tachometer to get a handle on my 904's quirks I noticed collant leaking by the heater core box.

I topped the system off and put another bottle of radiator stopleak in it and seems better since then. I've got heat and nothing is leaking for now. Obviously I'll be replacing all three, hopefully at the same time. Rad and Tstat have priority for now, might just bypass the heater core even though it's freezing, literally. Killed my already failing battery overnight :(

Piece by piece this car will be resurrected!
 
mullinax95 said:
I always dill a 1/16" hole in the thermostat to allow air to escape.
Click to expand...

Where exactly? I assume you close the hole but how? (otherwise once the air is gone the coolant wil escape)


My rad is shot, the coolant is brown and there was NO thermostat.

Going to flush the system and hope no passages are blocked.

Replace radiator (have new one) do a seperate oil cooler for trans, new Tstat 180* and new rad cap. Hope that does the trick.

Why would the PO have ran without a Tstat you think? It was going to be a drag engine build that never got off the ground is all I know...
 
DQ81 said:
Where exactly? I assume you close the hole but how? (otherwise once the air is gone the coolant wil escape)


My rad is shot, the coolant is brown and there was NO thermostat.

Going to flush the system and hope no passages are blocked.

Replace radiator (have new one) do a seperate oil cooler for trans, new Tstat 180* and new rad cap. Hope that does the trick.

Why would the PO have ran without a Tstat you think? It was going to be a drag engine build that never got off the ground is all I know...
Click to expand...


Hold the thermostat up like you are looking at a UFO and you will see the flat flange. The hole should be drilled between where the gasket seats and the main thermostat spring/bulb. You can take the thermostat housing and set the new thermostat down inside it and you will see where you need to drill the hole. Some thermostats come already come with a check valve so no hole needs to be drilled. I got a new thermo for my 03 Dodge Ram and it already had the small check valve.

Some people think that without a thermo that the motor will run cooler but that is not the case at all.
 
just my guesses.
1. the brown crap is stopleak.
2. the radiator and heater core are probable shot
3. the stopleak has plugged your engine and you will have to flush several times after you get the new heatercore and radiator in
4. All this is going to be expensive.
 
cuda65vpt said:
just my guesses.
1. the brown crap is stopleak.
2. the radiator and heater core are probable shot
3. the stopleak has plugged your engine and you will have to flush several times after you get the new heatercore and radiator in
4. All this is going to be expensive.
Click to expand...

Why guess when you can read a few posts back and see that you're right?!

As stated b4, rad is shot and I have a new one. Heater core leaks and I'm going to circumvent it untill I source a new one.

Expensive is a relative term. Sure ain't cheap.
Good call on the brown crap, hadn't thought of that...

Why clean the passages with a new rad and core in place? That will just get them dirty too!

How do you (all) advise I do a full flush of my engine block with the following limitations:

It's parked on a city street. (thankfully in front of my house) No garden hose, no high pressure hose.

I was thinking:

Top off the cooling system incl. a half can of system cleaner (no rad, so less cleaner)

As the rad is out I could use a longer piece of flexible rad hose and connect the bottom and top rad in/out directly. Run the engine for 2-3 minutes, drain all fluids and repeat process untill clean. Perhaps, carefully, disconnect the bottom hose to drain, have an assitant start the car and let the pump help get the gunk out, cut engine as soon as flow diminishes...

I wan't to do it this way so I don't en up possibly clogging the new rad etc.

Sound good? Should I do this with or without my new T-stat in place? (pressure wise)
 
DQ81 said:
Why guess when you can read a few posts back and see that you're right?!

As stated b4, rad is shot and I have a new one. Heater core leaks and I'm going to circumvent it untill I source a new one.

Expensive is a relative term. Sure ain't cheap.
Good call on the brown crap, hadn't thought of that...

Why clean the passages with a new rad and core in place? That will just get them dirty too!

How do you (all) advise I do a full flush of my engine block with the following limitations:

It's parked on a city street. (thankfully in front of my house) No garden hose, no high pressure hose.

I was thinking:

Top off the cooling system incl. a half can of system cleaner (no rad, so less cleaner)

As the rad is out I could use a longer piece of flexible rad hose and connect the bottom and top rad in/out directly. Run the engine for 2-3 minutes, drain all fluids and repeat process untill clean. Perhaps, carefully, disconnect the bottom hose to drain, have an assitant start the car and let the pump help get the gunk out, cut engine as soon as flow diminishes...

I wan't to do it this way so I don't en up possibly clogging the new rad etc.

Sound good? Should I do this with or without my new T-stat in place? (pressure wise)
Click to expand...
No outside gardenhose spigot? you poor cityboy:-D have any buddies in the country? I flush my vechicles in back yard. But now consious about well water contamination. anyhow, do you get prestone products? if so, they have back flush kits if you don`t mind a tee spliced in your heater hose. Leave old rad. in, and flush till clear. install new parts. bypass your heater core till you get a chance to put it in.
 
mopar head said:
No outside gardenhose spigot? you poor cityboy:-D have any buddies in the country? I flush my vechicles in back yard. But now consious about well water contamination. anyhow, do you get prestone products? if so, they have back flush kits if you don`t mind a tee spliced in your heater hose. Leave old rad. in, and flush till clear. install new parts. bypass your heater core till you get a chance to put it in.
Click to expand...

Indeedy, the tough life of a city boy. I have a backyard, well more like a patch of grass behind the backdoor, no hose will reach far enough :(

I think I can get Prestone stuff, I'll look into that tomorrow, I"m sure there's something like it in any case.

Thanks for the good advice!

Hopefully tomorrow afternoon the cooling system will be all set, then on to getting my vacuum advance to function properly, replace 904 with the one one the shelf (mpg's in the city) and then it will finally be time to get to a cam and intake :)
 
I thought I'd update and conclude this thread as often threads are left open ended and when searching you don't quite get answers...

So the symptoms were:

Not reaching above 130F

No real heat to speak of thru vents.

After turning the car off within about 5 minutes steam and dirty coolant would start spuwing out of the overflow hose and all over the street.

The first inspection of the system revealed the radiator was leaking and I assumed the Tstat was stuck open.

I sourced a replacement radiator from a stick vehicle and fitted an external oil cooler for the transmission. Both get excellent cooling from the electric fan fitted on the grille side of the radiator.

While I was changing the rad I obviously removed the Tstat housing: Empty! No Tstat, obvious reason for lack of proper temp (especially with the weather in the mid 20's)

Flushed the intere system with a garden hose with the car parked above a storm drain (90% of coolant was already drained) the storm drain thing was an excellent tip I got from a fellow city backyard mechanic, just point the lower rad hose at the drain and presto. Did this with the engine running and without untill the system was fully clear.

The main culprit was the radiator and cap. Being as leaky as it was and full of holes it was suckin in air and creating pockets of air which created the blow off after the car was turned off. The coolant didn't get warm enough but the trapped air sure did and found it's way out thru the overflow line and some leaks in the rad, result: coolant everywhere.

Installed new (to me) rad and brand new oil cooler, new 180* Tstat and gasket with origional housing, had to use silicon gasket to get it all to seal properly, finally new 1 bar rad cap. Cut the lines from the trans and mounted the cooler engine side and hooked them up using hose and clamps (wouldn't work on the other side with the electric fan) and I"m happy with the result. The flow is good and cooling is excellent.

Hoses and all are fine and so far on the one testdrive I've been on all is great. It did take quite a while to get up to temp but is very cold out, let it idle aprox 10 min still not above 140*, drove around for a few miles, not much change, let her sit at idle about 5 min later nice and healthy needle in the middle of the range on the stock meter and a big smile on my face, electric fan kicked on like it should and all seems well, heater core stopped leaking and coolant is a normal colour (slightly brown but that's not surprising).

Thanks greatly to all who chimed in, it was straight forward and easy enough to solve just that the symptoms were a bit strange at first.

David
 
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