Thermostat and engine coolant
02-12-2005, 06:53 AM
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Thermostat and engine coolant
Please bear with me, since I'm somewhat mechanical-challenged.
Does an engine coolant leak damage the thermostat if the coolant is below recommended level?Alternatively, will a broken thermostat cause an engine coolant leak?
The owner's manual recommended 50/50 (or more coolant, less water) water/coolant mix, with that in mind, is it normal to add the coolant mixture every few weeks?
Thanks in advance!
Does an engine coolant leak damage the thermostat if the coolant is below recommended level?Alternatively, will a broken thermostat cause an engine coolant leak?
The owner's manual recommended 50/50 (or more coolant, less water) water/coolant mix, with that in mind, is it normal to add the coolant mixture every few weeks?
Thanks in advance!
02-12-2005, 07:09 AM
#2
Answers?
1. An engine coolant leak shouldn't damage the thermostat unless the engine gets so hot it distorts the thermostat- VERY unlikely since you would damage many other things at that temperature.
2. If the thermostat is stuck CLOSED, then it could cause the loss of coolant by overheating it and boiling it off and forcing it out the reservoir cap. Have you noticed any steam?
3. It is NOT normal to need to add coolant that often- you likely have a leak somewhere (hoses and the plastic pipe between the oil cooler and the block are the most common leaks). Any drips on the ground? Last/least possibilities- head gasket (water in the oil) or transmission cooler (bad all around).
2. If the thermostat is stuck CLOSED, then it could cause the loss of coolant by overheating it and boiling it off and forcing it out the reservoir cap. Have you noticed any steam?
3. It is NOT normal to need to add coolant that often- you likely have a leak somewhere (hoses and the plastic pipe between the oil cooler and the block are the most common leaks). Any drips on the ground? Last/least possibilities- head gasket (water in the oil) or transmission cooler (bad all around).
02-12-2005, 07:13 AM
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Re: Thermostat and engine coolant
The thermostat is simply a heat operated valve... the hotter the coolant(water/anti-freeze mixture) gets the more open the valve becomes, allowing it to flow round the coolant system soaking up heat and transfering it through the radiator, this cools the coolant an amount which closes the thermostat a little which allows the coolant to heat up a little which closes the thermostat a little etc etc maintaining the correct and efficient engine temperature. In other words the thermostat itself can not cause a leak, even if it is stuck open or closed. What it can do is cook the engine itself if stuck closed.
Do you know where the coolant leak is? It is NOT recommended to run the car if the temperature can be allowed to run too hot (whether by having not enough coolant in the system or by the thermostat being stuck closed), serious damage can result in a whole new lump being required $$$$$$.
Your first job is to locate the leak. A hose split, hose clip loose, gasket etc, simply venting due to over temperature/pressure.
Try the question past us again with the above in mind, maybe I am mis-reading it.
PS
You don't need to worry too much about the exact ratio of anti-freeze and water at this stage (especially if it's leaking away) Too much anti-freeze is better than not enough as it stops corrosion as well as preventing the water from freezing.
Do you know where the coolant leak is? It is NOT recommended to run the car if the temperature can be allowed to run too hot (whether by having not enough coolant in the system or by the thermostat being stuck closed), serious damage can result in a whole new lump being required $$$$$$.
Your first job is to locate the leak. A hose split, hose clip loose, gasket etc, simply venting due to over temperature/pressure.
Try the question past us again with the above in mind, maybe I am mis-reading it.
PS
You don't need to worry too much about the exact ratio of anti-freeze and water at this stage (especially if it's leaking away) Too much anti-freeze is better than not enough as it stops corrosion as well as preventing the water from freezing.
02-12-2005, 07:51 AM
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You guys rock! Some more info...
I suspected leak on my father's car so we kept topping the coolant until we finally brought the car in for the repair (becasue the temp. gauge shot up, my father claimed it's normal for coolant to evaporate, but definitely not THAT much!). Dealer claimed the problem was caused by the faulty thermostat (2nd one in this car) and replaced it. Today, the coolant warning light came on again, so I'll have to see what happens if I top up the coolant today. I think the thermostat just happen to fail and it's a separate problem, hopefully, refilling the coolant will solve the problem. The dealer is going to hear from me if the coolant level continues to drop again after the repair. Since they didn't fix the problem...
02-12-2005, 08:15 AM
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Mmmm...
I suspect the thermostat replacement is still the problem. Take it back to the dealer me thinks, was it an Audi dealer?. The thermostat replacement is a long old job on these engines, are you sure it was done even?.
Maybe not seated properly in its housing and leaking, maybe stuck closed.
Keep an eye on the level and guage. If it rises while driving put both heater settings on MAX to draw off some heat. It will give you more time before you have to stop prior to overheating.
Maybe not seated properly in its housing and leaking, maybe stuck closed.
Keep an eye on the level and guage. If it rises while driving put both heater settings on MAX to draw off some heat. It will give you more time before you have to stop prior to overheating.
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02-12-2005, 10:23 AM
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Thanks again! I'll keep an eye on the level before I talk to the dealer
It looks like the dealer didn't top up the coolant so the warning light came on a few times when I was making sharp turns.