Technical Help identifying overheating issue?

[wired137]

Hi fellow owners, I inherited the vehicle and am decent with mechanics, looking for some advice here. Really I just need to drive it about 20 minutes to where I can really work on it. Might just do it over a few trips on a cool day.

It’s a 78 spider, car runs and rides great. From what I know, the thermostat was never fixed and instead radiator fan switch was wired up to a toggle in front. Unsure if radiator even works yet…pretty sure it’s shot.

I recently serviced fluids in the rear diff, master cylinder, oil.

I drove it around for 10 minutes or so, casual neighborhood driving. Head gaskets looks pretty new to me, haven’t identified an oil leak per se but it does look kind of moist Near and under head. I’ll have to try and start it cold and see what drips or drops.

Simply wondering at appearance if this looks like an overheating issue or simply fluid burn off from sitting. Temp gauge doesn’t move but I’ll do a resistance test on the ect if it has one (need to find shop manual / fiche)

 

[bugsymike]

That looks like a pretty hot engine to me, unless there is a lot of oil burning off the exhaust etc.
Generally if thermostat stuck closed, within 10 minutes or a quick run up the road it would be getting to the point where you can hear localised overheating banging etc, like central heating with air in.
As a quick guide from cold as engine warms up, top hose will start to feel warm first with bottom rad hose cold, but as thermostat opens both hoses should feel equally hot, just about bearable to the touch and both heater hoses should feel equally hot if heater temp set to high, but you wouldn't want to keep gripping the hoses.
Is it losing coolant, normally if thermostat stuck shut it will start to push coolant out of the radiator overflow.
Re trip to garage if coolant filled to brim and from cold with radiator fan turned on and heater set to hot and it's fan turned on, then if in a high gear/low revs and driven gently it may be enough to get you there, but do not turn on air con etc. as will make engine work harder and generate more heat.
Re the radiator it is quite common for old rads to have cooling tubes blocked internally with sediment, also same sediment can build up in the engine block affecting cooling around the cylinder bores etc.
Incidentally do not open the radiator pressure cap until much cooled down, as apart from burning yourself once the pressure is released the coolant will boil (10 lb cap equals approx. 115 degrees Centigrade before boiling against 100 degrees as usual) it is not the higher temp that damages the engine it is when that coolant boils and turns to a gas which is when the temp in the air bubble/gas around the cylinder head will reach much higher temp and damage the alloy cylinder head etc.

 

[wired137]

Thanks for that info, will be looking over everything as soon as I can get it to the garage. Engine temp gauge does work, car warms up to roughly 170-180 before I see the smoke. And the smoke is likely oil traveling from lower head to exhaust manifold.

Radiator fan works via manual switch (replaced fuse and it works well now).

Will be back here for more questions and posting! Probably going to replace the radiator…more troubleshooting needed. Unsure if water pump works either.