overheating?

[mc54]

Hi All

I have started to drive the FC as much as I can. Just to work out any bugs. Yesterday the temp light came on after about 20 kilometres. No real signs of overheating. A couple of drips from the overflow. Today was the same, around 20 kilometres and the light came on again. Drove for a couple of kms more and parked it for around 1/2 hour. Temp light was off when I started it up and drove it home. I let it idle for around 20 minutes. Light finally came on but still no real signs that it is overheating. Not sure what to do. Have done the welsh plugs and head gasket. Flushed out the block. Has a new thermostat. I did put stop leak in the radiator just as a precaution (I don't really like using additives)
Could this be causing a problem? I have also thought about putting a temp gauge in but I would like to keep it as stock as I can. The only thing I have not done is the radiator. It is a little soft at the bottom corner but otherwise appears OK.
Any advice would be appreciated.

Regards
Mike

[Just40]

best thing is to get a new radiator and new hoses, what the water pump like ?

[mc54]

Sorry, forgot to mention that the hoses and waterpump are new as well. Thought maybe the sender was defective? What are the chances of that?

Mike

[FX1975]

Flush all the stop leak out of the system as you may be restricting water flow somewhere and if your confident you have no leaks you don't need stopleak anyway.  The temp sender in the block could also be faulty so if you think everything else is fine replace this and see how it goes.
         If the light still comes on you must have a restriction somewhere slowing waterflow to the back of the motor.  Check or replace your radiator cap to ensure that the system is holding correct working pressure as this can also affect water flow as they are quite a low pressure system to begin with without losing any.

                                           Hope this helps
                                                    Frank

[Glenn 'Stinky' Stankevicius]

A little late now, but a good way to check your thermostat is to put it in some boiling water to see if it opens correctly before installing it.

Buy a cheap temp gauge and rig it up just to test the temp, or install it permanently in the engine bay.

[mcl1959]

This is a fairly common problem and I think it mostly stems from the temp sender being faulty coming on to early. The army FC had the same problem and I did all the things you have done and more - I was on the lookout for a NOS sender unit but sold the car before I found one.
Sometimes the light would come on and if I stopped turned the ignition off and then started it again the light would stay off - this indicated to me that the sender was playing up.

Ken

[sexyfc]

I agree with Ken, cheapest option would be to change your temp sender. But would be good to hook up a gauge to see what actual temperature its so called over heating at.
john

[mc54]

Thanks for the replies

I'm going to drain the system and remove as much of the stop leak and coolant as I can. Will be putting in water and inhibitor. I think I will try a temp gauge as well.

Regards
Mike

[mc54]

I have now drained the coolant and replaced it with water. I have also installed a gauge. It is running at 200° - 205°. This is on a 24° day.
I checked to see the temp range of the thermostat I put in (160°). I doubt that I put the thermostat in backwards but I will check that. Does
anyone have any other suggestions? The next step is a recore. The radiator is the only thing that has not been done.

Thanks

Mike

[FC427]

mc54 if you live in  Sydney I have a good radiator that has been recored you could try before you get your's done if you want to make 100% sure that is the problem  ......FC427......

[mc54]

Thanks, I really appreciate the offer but I was going to get this one redone sometime anyhow. It is a little soft in one corner and only has about a year or so left
in it. It is an original holden radiator - still has the metal tag with the part number on the core. I wonder if they will transfer it over to the new one.


Mike

[mcl1959]

A fairly rough way to test a radiator is to hold your hand over the bottom outlet and fill with water - release your hand and water should drain in a couple of seconds.

Ken

[mc54]

Have now put a recored radiator in and it is still running at 200°. The entire cooling system has been renewed.
Have installed a temp gauge and the thermostat opens at around 160°.
I'm going to check my timing but if I cannot get it to run any cooler will this temperature (200° to 205°) damage my engine?

Mike

[EffCee]

Mike, does your car have a heater, if so it may be holding air in the heater core. The heater core will need bleeding to get all the air out of the heater core. i have found that the most common culprits for this is the Bosch and Nasco types that have the circular heater.

To bleed the system is fairly basic, there are no bleed valves in the heater to my knowledge, the quickest way to bleed it is to disconnect one side of the heater with the engine running. Make sure that the engine is not hot, preferable having sat overnight so that you do not get scalded from an engine that is at operating temperature. You will only need to disconnect it for a couple of seconds, the rush of water travelling through the heater will be enough to bleed it.

Running the car at 200 to 205 degrees is starting to stretch the friendship.

[mc54]

No, I don't have a heater.

Damn, I really thought that when I put the new radiator in the problem was fixed. I found a radiator shop that has what he calls "vintage" radiators.
They are radiators that he recored many years ago for cabs. The one I got has a Nacso core. Same top and bottom tanks but the core is a lot wider than the one that was in my car.
Probably the correct width which has added a litre or so to my cooling capacity. When I idled it in the garage after the radiator went in (for around 20 minutes) the temperature stayed at 180°. But when I drive it it goes up, the thing is that it doesn't go above or below 200 by more than a couple of degrees, like it's supposed to be at that temperature.

I'm running out of ideas.
Even though the thermostat is new, maybe I should put another one in.
I know the timing is fully advanced right now, I will look at that this weekend.
The valve that is in the exhaust is seized, but that hasn't just happened, it's been like that for a long time.
I thought about the head gasket, but no oil in water or water in oil.
What are the chances of an air lock in the block?

Regards
Mike
 

[EffCee]

If the butterfly valve in the manifold is even partially stuck closed this wil make the engine run hotter, as it will create a restriction for the exhaust gases to escape.

Also having the timing "Fully Advanced" will also cause overheating issues. set the timing correctly and try again.

You state that you have just repaced the headgasket and other issues, was the engine overheating before the work was done, if so what were the symptoms.


To have a " blown" headgasket doesn't always mean that you will have water in the oil or vice versa. Headgaskets can leak from the combustion chamber to a water jacket, in between combustion chambers or externally.

To check for a leaking headgasket into the water jacket, I use a large funnel, that fits neatly into the radiator neck. I then fill the funnel, so that it is about 1/2 full and wait for any sign of air bubbles. A constant supply of air bubbles is normally a good indicator that you have a leaking headgasket, from a combustion chamber to a water jacket.

[mc54]

I took the head off to replace the welsh plug at the back of the head. I did notice that the old head gasket looked like it was burning between a couple of the cylinders. Unfortunately I cannot remember which ones.
The overheating started after the head was put back on, one of the new welsh plugs was weeping a little so I put some stop leak into the system. After a few trips out the temp light starting coming on. Might just be a coincidence.
I am going to redo the timing this weekend I will also do what you suggest with the funnel.

Mike

[FB_MAD]

200 to 205 degrees doesn't leave you with a great deal of safety margin however.....

Water, at sea level, boils at 212 degrees.

An engine will still run with no damage at 212 degrees however the biggest problem is that water also boils at that point producing copious amouts of air in the process.The air in the system then pressurises the cooling system further to a point where it blows the water out of the system via the radiator cap and outlet pipe leaving , eventually , more air in the system than water.The temperature of the engine rises very quickly then to a point where engine reciprocating parts clearances are taken up by metal expansion and the engine will then seize up.Lubricating qualities are also compromised with heat rise as well and the combination of the two will damage an engine.

To give further safety margins manufacturers raise the boiling point of water in a cooling system by pressurising the water via a pressurised radiator cap.
From memory, an FE/FC original cap is around a 7 psi cap??
This will raise the boiling point of your system.Its been so long since I studied at Tech I can't remember the exact amount that a 1 psi pressure increase will give to the boiling point of water but I'm guessing that a 7 psi radiator cap would increase the boiling point to around the 225 degree range or so.
Addition of Radiator coolant  (Ethylene Glycol) based in a 33% concentration is said to also help raise boiling point temp by around 15 degrees or so ( from memory ).

So with a good working pressurised radiator cap and addition of radiator coolant (in theory) your engines boiling point "SHOULD" be around the 240 degree range or so.

In your case follow the check methods of various parts/procedures that the other blokes have mentioned above, some of them may be the cause or part cause of the problems you're having.

You haven't mentioned the water pump yet.Does it look and feel like its in a servicable condition?? ( I've seen water pump impellers separate from drive shafts in cheap aftermarket water pumps in some red motor engines before).

When you replaced the welch plugs and had the head off did you pressure wash the head cooling ports and flush all the accumulated crap from inside the block cooling passages??

I recently did so in a 149 red motor of mine and got more than a 2 litre ice cream container full of muddy rust,rust flakes,remains of two old steel welch plugs,silastic blobs and pieces of head gasket material that a previous repairer was too lazy to take precautions to stop the old head gasket scrapings from going down the cooling ports.This 149 ( which is bored to 167 ) is currently in my FB Holden with a standard grey radiator and I don't even run a cooling fan at all ( some around town driving and some highway driving).It ran fine in last weeks multiple 40 degree days and sat on 88 degrees C most of the time, no problems.I firmly believe if I hadn't removed the crap from inside the block and head prior to installing the 149 into the FB then I would definately be having some system problems with it.

All the above crap I found in the 149 would have reduced the cooling system capacity by 2 litres,created hot spots in the lower end of the block and helped to eventually block the radiator cooling tubes with the rust flakes and bits of silastic and gasket material eventually making their way to the radiator and blocking it.

I modified a Torana radiator cap years ago in my first car ( FC wagon with 161 red motor) that was still running the original grey radiator but had some cooling problems.From memory the Torana cap was rated at 13 psi as opposed to the 7 psi FC cap.This modification helped and the cooling system coped with the increased pressure cap.I also knocked out welch plugs in the 161 and found heaps of shit in the bottom of the block.Pressure washed it all out,replaced welch plugs and removed top and bottom radiator tanks,unblocked cooling tubes reassembled and never had another problem with overheating in the 3 years I had the car.

[mc54]

The water pump is new.

When I did the welsh plugs I did clean out the block as well as I could but did not have a pressure washer. Used a garden hose.
Should I be running coolant or water with inhibitor?
Apparently coolant has a lower boiling point but retains heat more than water.



Mike

[FX1975]

       A garden hose is no where near as effective as a pressure washer when washing out blocks and heads.  also did you check that the holes in the new head gasket lined up with the water jacket holes in the block properly as this could also be effecting water flow if they are in the wrong spot or not thereat all.  I struck this a couple of years ago on a motor though it wasn't a grey. 

                               Regards
                                    Frank