Coolant smell, can't find a leak - 986 Forum - The Community for Porsche Boxster & Cayman Owners

BH2000S · 12-07-2015, 10:43 PM

New owner of a 2000 Boxster S with 54,000 miles. Engine was replaced at 29,000 miles, not sure why, possibly cracked head as oil and coolant were listed as mixed on the engine swap receipt that I have from the Porsche dealer.

Car had a dealer oil change and clean inspection 40 miles before I bought it. I've put about 1000 miles on the car, love it, no issues except I keep getting a whiff of coolant, usually with the top down so I don't think it is coming from the AC vents indicating a possible heater core issue. I've been watching the Porsche red coolant in the nice pristine white expansion tank, level does not seem to have dropped. It also does not seem to be using any oil.

Took it for a long drive yesterday, then it sat in the sun for about 5 hours. Started it and my passenger thought they saw a cloud of white smoke from the left vent, I doubt that could be the source, could have been oil in the exhaust that blew forward.

I pulled the engine cover, a bit dusty but no signs of leaks anywhere. I ran it with the cover off, nothing unusual. Exhaust was clear. Not sure where to look next. I'll put some tape on the expansion tank to watch the level more closely.

Anyone have any ideas?

JayG · 12-08-2015, 04:55 AM

Jack up the car, remove the plastic cover under the front of the engine and look at the bottom of the water pump and thermostat to see if there is any dried coolant.

Thinking back a little to before I replaced mine, I had a slight coolant smell every now and then and I did not see any level change in the tank. It turned out I had a very small shaft seal leak that got worse over time .

If you see any dried coolant, clean it off and check again in a few days assuming you have driven the car a bit

Luv2Box · 12-08-2015, 05:39 AM

Is the car a Tiptronic?

BH2000S · 12-08-2015, 07:37 AM

Quote:

Originally Posted by Luv2Box

Is the car a Tiptronic?

Manual 6 speed

BH2000S · 12-08-2015, 07:38 AM

Quote:

Originally Posted by JayG

Jack up the car, remove the plastic cover under the front of the engine and look at the bottom of the water pump and thermostat to see if there is any dried coolant.

Thinking back a little to before I replaced mine, I had a slight coolant smell every now and then and I did not see any level change in the tank. It turned out I had a very small shaft seal leak that got worse over time .

If you see any dried coolant, clean it off and check again in a few days assuming you have driven the car a bit

Thanks, I'll check this. What was the repair solution?

jdraupp · 12-08-2015, 07:43 AM

Quote:

Originally Posted by BH2000S

Thanks, I'll check this. What was the repair solution?

To replace your water pump

JayG · 12-08-2015, 07:47 AM

Quote:

Originally Posted by jdraupp

To replace your water pump

and the thermostat while you are in there

A reasonably easy DIY

I replaced my WP (Pierburg), thermostat and 3 gal of concentrated Porsche coolant was ~ $350

When the engine was replaced, did they reuse the WP? It is not that uncommon for that to happen

Conventional wisdom is the WP should be changed @ ~ 70k anyway

Flavor 987S · 12-08-2015, 07:55 AM

Coolant cap. Is it tight-tight? Make sure it's the newer updated cap ending in part number "04". Make sure cap is not cross threaded.

jb92563 · 12-08-2015, 08:19 AM

In the trunk by the Coolant/Oil cap there is a plastic shield.

If you remove that shield, under it you will find a coolant air relief/burp valve.

If it has crusty dried coolant in that area you have found the issue.

Either the relief valve gasket needs to be replaced, the screws need to be tightened, or the coolant system is overfilled.

If the coolant system is over filled you will get a release of coolant here and it will run down the drain tube and exit the car next to the rear right tire.

I had this happen after topping up the water tank and thought I had a more serious issue like a water pump failure. Once I realized what was happening I let it do its thing and it stopped leaking after the excess coolant was released.

I had kept on topping it off after each discharge thinking it was low and just continuing the cycle of discharging coolant after a drive.

JayG · 12-08-2015, 08:44 AM

Quote:

Originally Posted by jb92563

In the trunk by the Coolant/Oil cap there is a plastic shield.

If you remove that shield, under it you will find a coolant air relief/burp valve.

If it has crusty dried coolant in that area you have found the issue.

Either the relief valve gasket needs to be replaced, the screws need to be tightened, or the coolant system is overfilled.

If the coolant system is over filled you will get a release of coolant here and it will run down the drain tube and exit the car next to the rear right tire.

I had this happen after topping up the water tank and thought I had a more serious issue like a water pump failure. Once I realized what was happening I let it do its thing and it stopped leaking after the excess coolant was released.

I had kept on topping it off after each discharge thinking it was low and just continuing the cycle of discharging coolant after a drive.

+986, good catch

BH2000S · 12-08-2015, 08:33 PM

Thanks for all the great advice. I have not had time to jack the car up and check the water pump yet. I did check the burp valve (aka coolant bleeder valve?), totally clean. The expansion tank cap seems to seal fine but the threads seem a little wonky and the part number ends in 02 so I'll order the $27 updated Porsche one from Pelican. I don't really smell anything in the trunk.

I don't know if the water pump was replaced with the engine. The receipt notes a lot of hours cleaning coolant out of the oil system but not the water pump. I need to track down more info from a dealer.

If it is a small seal leak, I would be tempted to use a cooling system sealer but I'm guessing that will just cause problems down the road with a Porsche.

nieuwhzn · 12-08-2015, 09:52 PM

I have exactly the same problem. Bought the car 5 years ago, always smell a whif of coolant when starting. There is nothing, Nothing, that smells like a coolant leak anywhere. Leaks usually get worse over time, so after 5 years I kinda got used to it.
The only thing that I still have to look at is the overflow of the coolant tank. I found a tube that ends in the trunk but isn't connected on the other end, just strapped down under the engine somewhere.

JayG · 12-09-2015, 05:53 AM

Quote:

Originally Posted by BH2000S

Thanks for all the great advice. I have not had time to jack the car up and check the water pump yet. I did check the burp valve (aka coolant bleeder valve?), totally clean. The expansion tank cap seems to seal fine but the threads seem a little wonky and the part number ends in 02 so I'll order the $27 updated Porsche one from Pelican. I don't really smell anything in the trunk.

I don't know if the water pump was replaced with the engine. The receipt notes a lot of hours cleaning coolant out of the oil system but not the water pump. I need to track down more info from a dealer.

If it is a small seal leak, I would be tempted to use a cooling system sealer but I'm guessing that will just cause problems down the road with a Porsche.

Do not under any circumstances use cooling system sealer. That stuff can clog up places you don't want restricted.

If you do use it, please post your VIN so we know to avoid your car if you sell it

thstone · 12-09-2015, 07:05 AM

Had the same problem with coolant smell. Never a drip. This is what the underside of my engine looked like;

JayG · 12-09-2015, 07:18 AM

^^^^ Must be nice to have a lift at home

BH2000S · 12-09-2015, 11:47 AM

Quote:

Originally Posted by JayG

Do not under any circumstances use cooling system sealer. That stuff can clog up places you don't want restricted.

If you do use it, please post your VIN so we know to avoid your car if you sell it

I'll just put some oatmeal in the radiator like shoddy used car dealers used to do!

911monty · 12-09-2015, 12:08 PM

Black Pepper!

Xpit77 · 12-14-2015, 03:39 AM

Turn on the heater and fan and smell. If this is the strongest it may be the block heater.

BH2000S · 01-04-2016, 10:31 PM

I finally had a chance to jack up the car and pull the pan. Very clean underneath, nothing unusual found. No residue, no coolant smell. Hoses all appear to be in good condition. Pan just had road dirt on it, I cleaned it off and will recheck for any drips.

Since my original post, coolant has dropped about one line on the expansion tank. I still have not ordered the new cap, that could be the source. Not smelling much in the interior with the top up, still smell coolant at the side vents. The search continues.

Here are some really boring Porsche engine porn shots to prove I was under the car.

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