An idiot woman on my left turned right in front of my 987.2 S 2 months ago with damage to front left of car. In repair shop for 2 months. Picked up yesterday.

One mile from shop "Low Coolant" red msg. came on, temp needle pegged at 250 instantly after being in middle. Stopped engine. Cleared msg. Temp normal. This happened 2 times.

Later after driving for 20 min. with normal temp, temp quickly pegged at 250 again but no msg. or red warnings. Porsche friend driving. Pulled over, shut off engine. Waited few minutes, started engine, temp normal again - for a minute only. Repeat.

This time in traffic and could not pull over for a minute with temp at 250.

Shop says it was air bubble and they failed to fill coolant. They picked up car with flatbed. Said they's correct lack of coolant issue & I'll get car by end of day. Didn't happen, will get it today.

QUESTION: Is is possible my engine was damaged during this short over-heating? Once or twice temp was at 250 for a minute or so before we could stop engine. I've had this perfect car for 11 years and it's like new with 112k mile on it, no other issues. I've maintained it well. Uses 1/2 qt. of oil in 5k miles.

Woman hitting me didn't make me sick. But thought of damage to my engine does.

TIA,

GN

 

Crap like this will keep you awake at night!
On my 987.1, the coolant temp sensor is in the plastic manifold on the front of the drivers side of the engine. It is not measuring the temperature of the cylinder heads or block, per se.
The air bubble story does make sense. It is hard to get the coolant system filled.
If you really did drive a car around with no coolant, I think you would possibly lock up the engine or maybe warp the heads. Both would be pretty noticable.
Regardless, I would be nervous until things settle out.

My dad bought a new Pontiac Tempest wagon in Lynchburg, VA in 1965ish. One of the freeze plugs fell out a few miles from the dealership. The dealership put the plug back in and added coolant. He was an engineer and worried a lot about the whole episode but the car was with us for many years, so I guess it worked out.

 

Harvey -

You got that right! From now on I'll always be wondering - but glad to hear where sensor is - probably the same in a .2.

But if there - how does it get to 250 deg?

Like I said, first readings were clearly false. Shut engine off, turn back on, temp perfect.

Later ones - not so sure. Hope someone knows.

Thanks.

GN

 

AI

Coolant Temp Sensor Location 987.2

According to the search results, the coolant temperature sensor in the 987.2 Porsche Boxster is located on the pulley side of the engine, off to the left side of the car, near the cylinder head. This information is consistent across multiple sources.

Additionally, one source mentions that the sensor is held in place by a rubber grommet attached to the intake manifold on the right side of the engine, near the air pump. However, the majority of sources agree that the correct location is on the pulley side of the engine, near the cylinder head.

It’s essential to verify this information with a reliable repair manual or a Porsche-specific resource to ensure accuracy before attempting any repairs or maintenance.

 

The engine had coolant. But not enough. Temp was normal for 20 min. of driving. Shop said it was an air pocket in coolant, they had not properly bled & filled the system. I believe that.

GN

 

But if there - how does it get to 250 deg?

The sensor is designed to be immersed in fluid. No telling what happens when it is exposed to air.

PET 105-003 Item 8. I think you will find that item 3 is a plastic manifold that is bolted to the head/block. Visually, from the PET, the sensor is near the highpoint of the system, at least locally.

I listened to some CE during my nuclear power days about how difficult it is to get air bubbles out of fluid systems.

 

Fortunately these are pretty robust engines. I don't think I have heard of a warped head on these cars. Once the car is back, monitor for any coolant loss/smoke from tailpipe and get an oil analysis to see if there is coolant in your oil. Either may be indicative of a head gasket leak. I think you'll be fine though.

 

Thanks! Don't think it got that hot - was shut down quickly after temp peaked, Minute or so at most.

GN

 

When my 996 Turbo blew coolant out through cracked joins, my gauge went to cool ie no accurate reading. Maybe the 987.2 is the opposite?

 

If air bubbles remain in the cooling system of the Porsche Boxster 987, it can lead to inadequate engine cooling. Air bubbles can hinder the circulation of the coolant, resulting in overheating and potential engine damage. Additionally, the temperature gauge may display inaccurate values, complicating the assessment of the engine's condition. To avoid these issues, it is important to properly bleed the cooling system.
The cooling system in the Porsche Boxster 987 must be vacuum-bled. This ensures that all air bubbles are removed from the system, allowing for optimal engine cooling and preventing overheating. A special vacuum tool is used to bleed the cooling system and then fill it with coolant.

BR Michael
__________________
1994 993 3.6 Coupe
2008 987 3.4 Boxster S

 

Thanks Michael.

They did all that today. Still didn't fix problem. They told me all of this so it seems they know what they are doing. This is different crew than one that initially did the system.

GN

 

Did they lift the pressure release valve under the fill cap area?
This is critical for proper coolant fill.
also, there is a specific set of guidelines to use when starting the car, letting it idle, adjusting speed, etc.
Not my writing, but this is what I followed when I replaced my water pump.

"Now, fill the car up with coolant, until the coolant level is visible at the bottom edge of the coolant tank. Start the car and run it at idle, topping off the coolant to the maximum level, until no more coolant can be added. Rev the engine and let it settle down and top it off again if the level decreases. Be sure during the whole process that the car does not exceed 176° F (80° C) while bleeding the system: if the car gets too hot it will interfere with your ability to fill and bleed the system to the proper level.
Now, reinstall the reservoir cap and let the car continue to warm up at about 2500 rpm for 10 minutes or until the thermostat for the front radiators opens up. When the thermostat opens and coolant starts flowing forwards, the electrical radiator fans should turn on. Now allow the car to continue to warm up a bit more, revving the car to about 5000 rpm every 30 seconds or so. Remove the reservoir cap slowly, letting any built up pressure dissipate. There should not be any tremendous pressure built up because the bleeder valve is still open at this time. Top off the coolant in the tank to the maximum level, reinstall the cap, and repeat the process of revving the engine to about 5000 rpm for another five minutes.
Now, allow the engine to idle for a few minutes until you hear the radiator fans cycle on and off at least once. Turn off the engine, and slowly remove the reservoir cap again, relieving any pressure that might have built up there. Top off the coolant until it reaches the MAX level indicated on the coolant tank gauge, located on the side of the tank. Flip down the metal clip to close the bleeder valve and replace the "trap door" panel on top of the tank. If you have an automatic transmission car, then replace fuse B1 in the driver's side door kick panel.
I'm sure one question you're about to ask is "what type of coolant should I use?" The Porsche factory manuals indicate that the coolant used inside the Boxster engines should be considered a "lifetime" fluid, and mixing regular fluid with this life-time fluid is not recommended. I prefer to use the Porsche factory coolant in my cars. At $35 a gallon, it can be somewhat more expensive than generic coolant, but the Porsche coolant is not premixed. Plan on using about 19 liters (5 gallons) of coolant for cars without a center radiator (all 1997-04 Boxster). The 2005-08 cars and the Boxster S take about 22 liters (6 gallons) of coolant. Add one more liter as well if you have an automatic transmission. If ordering coolant for your flush job, I would be sure to order an extra gallon: you might need them to top off down the road, and the Porsche OEM coolant can be difficult to find in a pinch. The part number for a one gallon (3.79 liter) container is 000-043-301-05-M100, and it costs about $35 per gallon from PelicanParts.com. (Coolant can be either pink or green in color.)"

 

ClemCLone - a really great and detailed description of filling the cooling system. What is its origin, if I may ask?

BR Michael
__________________
1994 993 3.6 Coupe
2008 987 3.4 Boxster S

 

Clem -

I have no idea, not present when they did this. Thank you for this, I will print it out and take it to them

Priceless.

GN

 

I don't remember. I did this in June of '22. I did a search for this, and this article came up. It was either in this forum or Planet-9.