Loss of coolant

[aps1231]

Hello everyone,

I have a Boxster 1998, manual transmission.

I just took it to the 60,000 miles service, and the car ran like a dream for about two weeks, with the help of new tires and new spark plugs.

Then it suddely started to run hotter than ususual, and the fans kicked in, keeping the temperature around the second white mark (~ 200F?). I added up about 1 gallon of coolant, drove it to the shop, and had to stop after 3 miles as the temperature started to rise fast. Coolant was dripping profusely from under the car, and seemed to come from the expansion tank. I got it towed. The shop pressure tested it, let it run for 45', drove it around and couldn't find anything wrong. To be on the safe side, they replaced the thermostat, the pressure cap and the bleeder valve.

I drove about 20 miles without any problem, temperature normal (although a little bit higher than it used to). I then noticed the coolant level was low and added 3 cups of coolant to bring it half way between Min and Max.

I then drove 2 miles, shopped for about an hour, then drove home. Again temperature was normal, but the coolant was all over the drive way! I let it cool down, removed the pressure cap, started the engine (with the level slightly above the bottom of the expansion tank). It ran for a few miinutes, temperature ~ 185F, then suddenly the coolant shoot up and spilled all over the trunk and into the driveway.

I checked the oil: clear like new. I didn't see any trace of oil in the coolant either. Likewise, no steam coming out of the exhaust, and the engine starts and run perfectly smooth.

Next step, I'm going to take it back to the shop, where they will check for air pockets in the coolant (but why do I have suddenly air in the coolant?), as well as an analysis of exhaust gases for water + analysis of coolant for the presence of hydro carbons.

Also, why is it intermittent and sudden? If that was a head gasket leak, wouldn't this problem be permanent? Is a head gasket failure common with the Boxster, after only 60,000 miles of conservative driving (I never rev it up above 5,000 rpm, and normally shifts no higher than 3,000 - 4,000 rpm).

Also, why did it happen just after the 60,000 service? What could have triggered this?

I would appreciate any hint, suggestion or similar experiences (and fixes).

Thanks.

[1schoir]

Hello everyone,

I have a Boxster 1998, manual transmission.

I just took it to the 60,000 miles service, and the car ran like a dream for about two weeks, with the help of new tires and new spark plugs.

Then it suddely started to run hotter than ususual, and the fans kicked in, keeping the temperature around the second white mark (~ 200F?). I added up about 1 gallon of coolant, drove it to the shop, and had to stop after 3 miles as the temperature started to rise fast. Coolant was dripping profusely from under the car, and seemed to come from the expansion tank. I got it towed. The shop pressure tested it, let it run for 45', drove it around and couldn't find anything wrong. To be on the safe side, they replaced the thermostat, the pressure cap and the bleeder valve.

I drove about 20 miles without any problem, temperature normal (although a little bit higher than it used to). I then noticed the coolant level was low and added 3 cups of coolant to bring it half way between Min and Max.

I then drove 2 miles, shopped for about an hour, then drove home. Again temperature was normal, but the coolant was all over the drive way! I let it cool down, removed the pressure cap, started the engine (with the level slightly above the bottom of the expansion tank). It ran for a few miinutes, temperature ~ 185F, then suddenly the coolant shoot up and spilled all over the trunk and into the driveway.

I checked the oil: clear like new. I didn't see any trace of oil in the coolant either. Likewise, no steam coming out of the exhaust, and the engine starts and run perfectly smooth.

Next step, I'm going to take it back to the shop, where they will check for air pockets in the coolant (but why do I have suddenly air in the coolant?), as well as an analysis of exhaust gases for water + analysis of coolant for the presence of hydro carbons.

Also, why is it intermittent and sudden? If that was a head gasket leak, wouldn't this problem be permanent? Is a head gasket failure common with the Boxster, after only 60,000 miles of conservative driving (I never rev it up above 5,000 rpm, and normally shifts no higher than 3,000 - 4,000 rpm).

Also, why did it happen just after the 60,000 service? What could have triggered this?

I would appreciate any hint, suggestion or similar experiences (and fixes).

Thanks.

Aps:

Your first problem was probably caused by a faulty (or outdated) coolant cap (i.e., NOT an 001 cap). That is probably why they didn't find any problem the first time when they tested it with their equipment: their pressure tester eliminated the coolant cap out of the equation.

Now that you lost all of that coolant, it's most likely that it is air trapped in the coolant lines that is causing your current symptoms. You can either try to bleed it yourself by driving around with the bleeder valve open for a few days and refilling when needed, or you can make sure that the shop uses the vacuum method for refilling your coolant.

Do a search here and you will find plenty of information on bleeding the air out of the system.

Regards, Maurice.

[aps1231]

Hello everyone,

I have a Boxster 1998, manual transmission.

I just took it to the 60,000 miles service, and the car ran like a dream for about two weeks, with the help of new tires and new spark plugs.

Then it suddely started to run hotter than ususual, and the fans kicked in, keeping the temperature around the second white mark (~ 200F?). I added up about 1 gallon of coolant, drove it to the shop, and had to stop after 3 miles as the temperature started to rise fast. Coolant was dripping profusely from under the car, and seemed to come from the expansion tank. I got it towed. The shop pressure tested it, let it run for 45', drove it around and couldn't find anything wrong. To be on the safe side, they replaced the thermostat, the pressure cap and the bleeder valve.

I drove about 20 miles without any problem, temperature normal (although a little bit higher than it used to). I then noticed the coolant level was low and added 3 cups of coolant to bring it half way between Min and Max.

I then drove 2 miles, shopped for about an hour, then drove home. Again temperature was normal, but the coolant was all over the drive way! I let it cool down, removed the pressure cap, started the engine (with the level slightly above the bottom of the expansion tank). It ran for a few miinutes, temperature ~ 185F, then suddenly the coolant shoot up and spilled all over the trunk and into the driveway.

I checked the oil: clear like new. I didn't see any trace of oil in the coolant either. Likewise, no steam coming out of the exhaust, and the engine starts and run perfectly smooth.

Next step, I'm going to take it back to the shop, where they will check for air pockets in the coolant (but why do I have suddenly air in the coolant?), as well as an analysis of exhaust gases for water + analysis of coolant for the presence of hydro carbons.

Also, why is it intermittent and sudden? If that was a head gasket leak, wouldn't this problem be permanent? Is a head gasket failure common with the Boxster, after only 60,000 miles of conservative driving (I never rev it up above 5,000 rpm, and normally shifts no higher than 3,000 - 4,000 rpm).

Also, why did it happen just after the 60,000 service? What could have triggered this?

I would appreciate any hint, suggestion or similar experiences (and fixes).

Thanks.

Aps:

Your first problem was probably caused by a faulty (or outdated) coolant cap (i.e., NOT an 001 cap). That is probably why they didn't find any problem the first time when they tested it with their equipment: their pressure tester eliminated the coolant cap out of the equation.

Now that you lost all of that coolant, it's most likely that it is air trapped in the coolant lines that is causing your current symptoms. You can either try to bleed it yourself by driving around with the bleeder valve open for a few days and refilling when needed, or you can make sure that the shop uses the vacuum method for refilling your coolant.

Do a search here and you will find plenty of information on bleeding the air out of the system.

Regards, Maurice.

Thank you, Maurice. This is very helpful, and giving me hope that it has nothing to do with the head gasket. I'll do as you suggested.

Alain

[kbrandsma]

Remove carpet from trunk and check under the trunk board for any coolant, if so you might have a faulty reservoir tank which is fairly common.

[aps1231]

Remove carpet from trunk and check under the trunk board for any coolant, if so you might have a faulty reservoir tank which is fairly common.

Thank you.

I had the reservoir replaced last year (cracked). This time, the coolant is definitely coming thru the overflow. It looks like there's an air pocket (or combustion gases) in the coolant system. The question is: how did it get there in the first place. Next step is to bleed the system, and analyze exhaust gases and coolant.

[1schoir]

...

The question is: how did it get there in the first place.

...

Alain:

If the coolant cap is not making a good seal on the coolant reservoir neck, after a drive it can suck additional air in to the system. I think that after the car cools down and has sucked in all the air, the air then expands inside the system and then forces the coolant to overflow.

Regards, Maurice.

[carlosvquezada]

I hope you don't mind me jumping onto this thread, but I have a related issue and need a little help. I have noticed a steadily rising running temperature for about a month and finally last night I got a nice steam bath from the back of the car and all my coolant dissipated. I can see water leaking near where I am guessing the cooling system enters the tranny. (tiptronic btw) Any ideas what may have caused this or if it might be symptomatic of other issues besides just age and the car being driven like a Porsche?

About 14,000 miles ago I had the tranny rebuilt (heavily damaged torque converter) and replaced a 2.5L with 2.7L after IMS failure. Pedro Hi-Flow intake, and Crios exhaust mod.

I attached a picture of where it looks like the water is coming from. Any advice as to getting to that hose would be appreciated as well. (i.e. how difficult is it too remove that lever that's sitting in front of it? looks like a B)

I'm recently unemployed so I have the time to diy and not the money to take it to a shop. As such your comments are very much appreciated. Thanks