Fixing an Overheating Car

[Starwhip]

About thirty minutes ago my father tasked me with figuring out why my grandfather's... maid's(? I don't know the technical term. :|) car was overheating. I've got two different repair manuals for two cars that are not the model of the car I'm attempting to "fix"...

Here's what I've figured out and done so far before it started thunder-storming:

• The coolant level was in the right spot
  
• The top of the coolant tank where the hose comes out of was corroded
  
• The inside of the cap on the other side of the hose (where it enters the grill area, I believe) and the place where the cap screws in are corroded
  
• The coolant/water inside the tank was rusty
  

I flushed out the tank with a garden hose to get rid of the rusty water and cleaned as much of the corrosion away as I could. Still need to run the car for a while to see what happens.

Do any of you guys have some pointers?

[Tex_NL]

The waterpump might be stuck preventing the water to be circulated.

The radiator fan might be broken, not cooling the water enough.

The radiator fan switch could be broken not switching the fan on.

The radiator thermostat could be malfunctioning not sending the water through the radiator to be cooled.

There are many reasons it runs hot. Only way to find out what is through a process of elimination.

[Kerbart]

Add some radiator panels?

[benzman]

There are whole lot of reasons why a car will overheat but, as you say the water was rusty, the most obvious reason is that the inside of the engine block and the radiator core are partially blocked by rust. Flushing with clean water will not move this rust. You will need to get a radiator cleaning compound from a car accessory shop. follow the instructions and after you drain the water, which should be very rusty, repeat the process with more compound. If the water drains clean after the second go you should be all clean inside. If the car still overheats things will get a bit more difficult!

[Starwhip]

There are whole lot of reasons why a car will overheat but, as you say the water was rusty, the most obvious reason is that the inside of the engine block and the radiator core are partially blocked by rust. Flushing with clean water will not move this rust. You will need to get a radiator cleaning compound from a car accessory shop. follow the instructions and after you drain the water, which should be very rusty, repeat the process with more compound. If the water drains clean after the second go you should be all clean inside. If the car still overheats things will get a bit more difficult!

Hmm... maybe. In which case it's beyond me to fix.

We'll find out eventually, it's still pouring.

[LordFerret]

I would start with the thermostat, a simple fix - cheap part, plus you'll need a replacement gasket. Make sure the replacement part is of the proper temperature for the engine (check specs).

The water pump; If you can turn it by hand (might need to loosen the belt(s) first), then that's not the problem. If you can't turn it, a jammed or frozen impeller is likely ... I find them an easy swap, like the thermostat, you'll need a replacement gasket and go visit an auto junk yard for a replacement pump (used are usually just fine, cheap too).

Radiator fan is an easy check; If the car's hot, it should be running. If not, check the fuse panel first. Another related problem would be the temperature sending unit/switch; That's another easy fix (usually), if you can get to it. If all else fails - the fan could be shot.

Checking the radiator core is a bit more difficult. That's really something you should let a shop do. If it's clogged, they might be able to clean it out - and then pressure test it, especially if it's badly rusted. I think more-so than the fan, the radiator core will likely be the most expensive repair issue.

Been there, done that, many times ... skinned knuckles to prove it lol.

Good luck.

[r4pt0r]

I once replaced a radiator fan that went out....the new one still didn't work. Seems I just needed a 30 cent fuse

Dont do what I did, check the cheap fixes first lol.

[LordFerret]

I forgot to mention this (an old stand-by) Chilton Manuals.

[Starwhip]

May have found the issue: There are missing belts.

EDIT:

Nevermind, there are a few leaks in the cooling system. One in the radiator fan, and one near the engine block.

Edited June 26, 2015 by Starwhip

[Frybert]

What do you mean leak in the radiator fan?

[Starwhip]

What do you mean leak in the radiator fan?

There is steam coming up through the fan. Not IN the fan per se, but near it.

[DarkGravity]

There was a leak AND the coolant level was in the right spot?

[WinkAllKerb'']

it's like trying to fix the heat flow from the source na ? could work sometime ; )

Edited June 27, 2015 by WinkAllKerb''
...

[steve_v]

...there are a few leaks in the cooling system. One in the radiator fan, and one near the engine block.

As others have said, check the thermostat - take it out (cold) and drop it in a pot of water at or just above the marked temperature. If it doesn't move, bin it.

Leaks are a problem, leaks around the hub of the (presumably belt driven) fan may well be from the water pump seals / bearings as it's often driven on the same shaft. - Hint: most water pumps have a "telltale" hole in the bottom of the housing where the shaft exits, if it's leaking water here the seals are shot.

If it's not the water pump, it's probably from the bottom hose (easy) or radiator core itself behind the fan somewhere... Which does not bode well for the condition of the radiator as a whole.

Also check the heater connections/hoses, as they are a very common source of leaks.

Use a radiator flush compound, then try "back flushing" (reverse direction to normal coolant flow) until no more rubbish comes out. Getting rid of the rust may of course exacerbate leaks.

There are products that claim to "plug leaks" in a radiator from the inside, but they're a stopgap measure and may cause more problems than they solve - by "plugging up" things that shouldn't...

If it's leaking from the radiator where you can get at it, you may be able to solder it up the old-school way - but YMMV with a modern vehicle.

Any DIY radiator repairs are, of course, just until one can find a replacement at a reasonable price

Minor leaks shouldn't cause the engine to overheat alone (provided you keep the coolant topped up), but they may be indicative of a more systemic problem - heavily corroded cooling galleries and/or radiator passages.

Has it had a proper glycol (antifreeze) mix in it? Modern cars with alloy heads pretty much require it for it's corrosion inhibiting properties, and it's a good idea even in an old cast iron beast.

One other thing that may cause overheating is a blown / leaking head gasket. Top it up, make sure all the belts are in place and run the engine with the radiator cap off. Check for bubbles or oil in the water, and water in the oil. Either of these probably means replacing the head gasket and checking the block / head for cracks.

A compression test or a "leakdown test" should be done if you suspect this is the problem.

Just to muddy the waters further, a flogged out water pump seal can also draw air into the system with similar results - make sure this is ok before getting more serious.

Edited June 27, 2015 by steve_v
Thermostat first, most common.

[Dispatcher]

All the above is good advice. If you've done the less challenging, less expensive options and still have problems, then the last thing to replace is the radiator. I've done that myself; not too hard and not as expensive as having a shop do it.