I know overheating has been a pretty hot subject lately, and I apologize for any redundancy. i've had all the symptoms everyone else has been getting but it turns out it's just the gauge. I know it's not my gauge, because the increase in temperature is gradual over a 6 mile drive. By the 7th mile the temp gauge has reached the maximum position. This was after I replaced the thermostat. Before the replacement the temp gauge would rise to about maybe 4mm before the top. After the replacement, the needle goes all the way. My dad told me to try leaving the thermostat out. Any thoughts of this approach? Keep in mind I am located in Phoenix, AZ where it can get to 115F and feel like 115F(dry heat, not farse heat generated by humidity), so I'm not too concerned with warming up.
Pros and Cons of no Thermostat
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If replacing the themostat didn't fix the problem then it wasn't the problem. Getting rid of the themostat might be a quick fix but I wouldn't recomend it for the same reasons john-w mentioned as well as with no regulation its going to experiance swings in tempature and this causes undue stress on your engine.
Have you checked and made sure the fans are working? And has the coolent system been flushed recently? Proper coolent mixture in it?
There are also two thermastats. An 89 deg and a 82 deg, could you have had the 82 in the car before and replaced it with an 89? This shouldn't cause it to overheat by itself but with a weak coolent system you might get the extra 4mm.
If I had to guess I'd say the radiator is probably getting restricted and built up with deposits. Kind of like shower heads and sinks do in hard water areas. I've seen the insides of radiators that have ran their life and its not a pretty sight. Best thing to due is to replace it, though if your handy with a torch you can open most radiators up and rod them out, but I'd just replace it. Much easier.
But check the small things first.
I've noticed an interesting trend lately too, I'm not saying this is your problem, but I though I might throw it out on this thread since relates to the cooling system and coolent minded people will be looking at it.
Some of you might remember I've been having some head issues. I'm gradually getting all that sorted out.
But its given me the chance to view 3 different heads, a 4th probably tommorow, I better see it tomorrow. :x (loooong story)
Anyhow, the coolent passages on all the heads were all almost totally plugged with deposits. The one I pulled from my car only had one passage open. The others were similar, only a couple passages open, all the others clogged. I know some build up is to be expected, but this is total blockage, it seems to build right where the head gasket is and forms kind of an extention of the gasket.
Has anyone else noticed this?
My car wasn't having any overheating problems, it ran about 1/2 on the gauge, maybe a bit over.
But how are they running if they are so clogged up? And isn't the extra restriction going to increase system pressures dramatically? I'd think it would be overheating dramatically if it was that clogged??
Have you checked and made sure the fans are working? And has the coolent system been flushed recently? Proper coolent mixture in it?
There are also two thermastats. An 89 deg and a 82 deg, could you have had the 82 in the car before and replaced it with an 89? This shouldn't cause it to overheat by itself but with a weak coolent system you might get the extra 4mm.
If I had to guess I'd say the radiator is probably getting restricted and built up with deposits. Kind of like shower heads and sinks do in hard water areas. I've seen the insides of radiators that have ran their life and its not a pretty sight. Best thing to due is to replace it, though if your handy with a torch you can open most radiators up and rod them out, but I'd just replace it. Much easier.
But check the small things first. I've noticed an interesting trend lately too, I'm not saying this is your problem, but I though I might throw it out on this thread since relates to the cooling system and coolent minded people will be looking at it.
Some of you might remember I've been having some head issues.
I'm gradually getting all that sorted out. But its given me the chance to view 3 different heads, a 4th probably tommorow, I better see it tomorrow. :x (loooong story)
Anyhow, the coolent passages on all the heads were all almost totally plugged with deposits. The one I pulled from my car only had one passage open.
The others were similar, only a couple passages open, all the others clogged. I know some build up is to be expected, but this is total blockage, it seems to build right where the head gasket is and forms kind of an extention of the gasket.Has anyone else noticed this?
My car wasn't having any overheating problems, it ran about 1/2 on the gauge, maybe a bit over.
But how are they running if they are so clogged up? And isn't the extra restriction going to increase system pressures dramatically? I'd think it would be overheating dramatically if it was that clogged??
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The plugged head coolant passages will probably be because (a) tap water was originally used in the mix, and (b) the coolant wasn't changed when it should have been. Those two reasons are also probably why those heads are now available as spares :roll:
I hate to say this, due to your recent experience, but: an engine shop would be able to hot-tank the head which would remove all scale from the coolant passages.
I've never seen a cylinder head with plugged-up coolant passages. For sure it'd cause the engine to run hotter. Ironically though those plugs could have protected the engine from damage: the higher water pressure due to the blockage would prevent the formation of steam pockets in the cooling system. Such localised boiling-points can severely damage an engine, including cracked heads and blown headgaskets.
I wonder if the higher rate of cracked 8v heads is due to localised boiling in the head?
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I hate to say this, due to your recent experience, but: an engine shop would be able to hot-tank the head which would remove all scale from the coolant passages.
I've never seen a cylinder head with plugged-up coolant passages. For sure it'd cause the engine to run hotter. Ironically though those plugs could have protected the engine from damage: the higher water pressure due to the blockage would prevent the formation of steam pockets in the cooling system. Such localised boiling-points can severely damage an engine, including cracked heads and blown headgaskets.
I wonder if the higher rate of cracked 8v heads is due to localised boiling in the head?
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lol I'm not tooo traumatized by the event, I figure what goes around comes around, I did everything I could, it's on their head now.
I've found a small shop thats a little more local, the owner seems to be an honest fellow, I had them resurface and dip my last head, the one the cam gear sheared off and knackered it all up.
That was a really nice head. I'd replaced the seals, lapped all the valves in, had it dipped and resurfaced as I said above. Painted it a nice red. I really liked it. I am still a little wary though. I've started the practice of stripping everything off the head before I take it in, I figure they can't damage much if there isn't much there. Baggie the valves and put the lifters in an oil bath and give them a bare head, it worked last time.
I'm going to have the cam gears dye checked for cracks this time around.:roll:
I'm trying to think if I broke a mirror or something lately this run of bad luck has been unbelivable....
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Buy a new radiator. Aluminium or copper doesn't matter - just buy a new one! Nissens is a good brand.
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You might not want to try this on your beloved Saab, but it worked a treat on my old Golf...Matthew said:
Fill the cooling system almost full, and empty three or four packets (ie sachets) of kettle de-scaler into the tank. Run for a while, flush with plenty O' water. Cleaned out the pipes of that puppy, all nice and shiny. Found all the leaks to boot. You wont find that in Bently, Haynes or any other service manual... nor would Saab or VW suggest it, but it worked for me!
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