Technical Question - Blinking overheat light when temperature is normal

So I have this problem I am hoping some had before or knows the solution to. This has happened to me twice so far. Sometimes when I drive my car the red light on the 'hot' end of the temperature gauge (right side) start blinking even though the needle on the temperature gauge shows that the car's internal coolent temperature is only around 190 degrees or so, which based on the meter is the middle 3rd of the temperature gauge - well within normal. When I park the car and get out the fan in front sounds like it's on full blast. I can't figure out what the problem is... any suggestions? Thanks!

low coolant

Thanks Robyn C - so there's no gauge or light that comes on to say low coolant, just the blinking lights? What type of coolant should I buy?

+1

Porsche has it's own coolant...so you could pop by a dealer and pick some up. I have heard Pentosin...but I don't know much about it.

Beware - you could have a leak or you could potentially have oil + coolant intermix - this is what my car did and led and looking into the cause helped me to discover my needing a new engine. Check your oil and pray that you see normal looking oil. If it is foamy and frothy, sit dow and take a deep breath. Then get the car to a garage pronto.

low coolant. just had the same thing, had a leaking overflow tank. unfortunately over$ 300 for the tank. but it solved the problem. you could also check your coolant level regularly while the engine is cool, in unpressurized mode and keep a gallon of coolant in the trunk. much cheaper, but temporary fix. bob

There are many threads on this, it can be low coolant ore hight temps in the engine compartment as well. Unless you do a coolant system flush only use porsche coolant as an additive. BTW there is also a fan mod to automatically run your fans at will. 996s fans come on late in the game, especially if you live in a high temperature climate.

I have also had this problem, even though the coolant temperature was not too hot, and not other coolant leaks. My mechanic advised to check the engine compartment sensor located on the passenger side, top of the engine, between the first and second intake manifold ducts. It can slip out of its gromet, causing it to actually rest on the engine, which will cause the computer to think engine compartment temps are too high. good luck.

Bringing back a very old thread from the dead. On hot days I sometimes get the slow blinking light. Coolant is at the correct level, and I do not see any signs of leaks around the expansion tank or cap. So that means it is the engine compartment blower fan not coming on. Which makes sense, because I can't recall ever hearing it run in the 3 years I have owned the car. What is the fix for this? Is there a relay that is bad? Does the entire blower need to be replaced? Could the temp sensor be the culprit? Most of my research around the temp sensor says that it usually falls onto the engine and reads too hot and fan runs too often. I seem to have the opposite problem. BTW car is a 99 C2 coupe. Thanks in advance for the help, Alex

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Check your fuses/relays for the fan. I hear mine click on after I park the car.

The coolant gauge light blinks for different things. I will look it up and post.

Four functions of the coolant warning light: 1. Engine coolant level too low; light flashes slowly (0.5 Hz) 2. Engine compartment temperature too high; light flashes slowly (0.5 Hz) (engine compartment blower might be faulty) 3. Engine coolant temperature too high; light is lit; pointer on the right 4. Temperature sensor at water outlet faulty; light flashes rapidly (1 Hz); pointer on the right Note The temperature warning in point three is indicated if the conditions "engine coolant temperature too high" and "engine coolant level too low" are present simultaneously (1Hz = 1 flash per second. 0.5Hz = 2 seconds per flash).

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Correct. Slow blinking is attributed to either low coolant or engine compartment temp too high. Fast blinking is temp sensor at water outlet faulty and the light constant on is the coolant temp too high. Mine is showing the slow blinking that seems to be more frequently attributed to low coolant level or a leaking expansion tank. I have ruled both of those out so I believe the issue is with the engine compartment temp. I don't recall ever hearing that fan run so I am looking to figure out the next steps.

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Checked the fuses and they are fine. I didn't see a relay on the fuse box diagram. Is there one somewhere other than the fusebox?

I'm running into the same problem- slow blink all the time, coolant level is correct, no cracks in tank (just replaced), engine temp sensor is fine, and the engine bay fan works (tested with scantool). Going a bit crazy tracking down the problem- perhaps the new coolant sensor was defective? Just received a replacement and am going to swap it out.

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^^ Rear parcel shelf (under foam/carpet cover)...