[Gentleman Driver]

I searched here and other places and didn't find anyone with an instance of coolant exploding in the engine bay and it all running onto the ground... but sorry if this has been discussed before.



I just did some maintenance on my car, and took it out to see how it responded to everything... drove it pretty hard, but the water temp never got to mid-point and there were no signs of anything going wrong. As I pulled into my house, all of the sudden I see smoke coming from under the hood... oh crap!

Popped the hood only to hear the wonderful crackling sounds of coolant hitting a hot engine, and looked underneath the car to see the coolant just gushing out onto the pavement. Lucky me this happened at night, I park outside, and couldn't find my flashlight.



Going to take a look around once it gets lighter here, but does anyone have an idea about what could cause this? Seems to be rare, since I could not find another story about it, but I did read about either the Heater Control Valve or the Lower Radiator Hose going...



FYI, the list of things I did to the car last weekend, in case any could have an effect (doubtful):



Oil Change - 10w40 Royal Purple

Gear Oil Change - Mobil 1 75w90 LS

A/C and PS Belt Changes

Intake Mod



Thank you in advance for any assistance!

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[flash]

there are a lot of places you could have gotten a leak - definitely need to poke around and see if you can figure out the area of origin, so we can narrow it down

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[PorscheDude]

Check the heater control valve.

I had this happen to my old 944.



Lucky it is much easier to change in the 968.

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[Gentleman Driver]

[quote name='PorscheDude' post='64437' date='Dec 20 2008, 10:51 AM']Check the heater control valve.

I had this happen to my old 944.



Lucky it is much easier to change in the 968.[/quote]



Thanks guys, going to take a look. I think I read the HCV is behind the oil filter, is that right?



BTW, I have the workshop manual, but is there a source for an engine diagram and location of all of these parts?



Thanks again! I will report back soon...

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[flash]

yes, it is behind the oil filter



not sure if there is such a diagram there or not - i have seen a cooling system diagram though, and i will look for it

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[Gentleman Driver]

[quote name='flash' post='64441' date='Dec 20 2008, 11:03 AM']yes, it is behind the oil filter



not sure if there is such a diagram there or not - i have seen a cooling system diagram though, and i will look for it[/quote]

HCV looked fine, but what do I know... there was no fluid around it, nor on the oil filter, but somehow fluid got on the headers and spewed up everywhere.



Can you visually see anything on the HCV to indicate that it has gone bad? I do all of my maintenance / car work at friend's houses seeing I am poor and don't have a garage, tools, etc... the only person close enough to drive to is gone until after New Year's, and I doubt I could drive to my other friend's place which is 20 miles away... I will put some coolant in and see if it just pours right back out.



What type of coolant (hopefully cheap since it will run right out) should I put in?



I think it is obvious I need to get it on jack stands and see what is going on underneath where all the fluid is (around the Power Steering unit, lower pan, etc). Are there any hoses down there that run the coolant?



I know I had air in the system, as I would get a sound of rushing water from time to time, wonder if that has anything to do with it...



Car will be down for a while, until my friends return. Now it is time to drink...

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[968rz]

Couldn't you use the compressor to pump up the coolant system and find the leak that way? Put the hose end in the over flow tank and seal it best you can then turn it on and watch for leaks (no mre than 12lb!!!)

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[Gentleman Driver]

[quote name='968rz' post='64453' date='Dec 20 2008, 01:40 PM']Couldn't you use the compressor to pump up the coolant system and find the leak that way? Put the hose end in the over flow tank and seal it best you can then turn it on and watch for leaks (no mre than 12lb!!!)[/quote]

Don't have a compressor... and I assumed since it was spewing everywhere the blown part would be easier to identify once I got under the car.



Thank you for the suggestion!

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[968Syncro]

Had two of these in the last year on other cars:

- 944, was a heater hose right under the valve cover. Whew! this was really lucky, thought it was the water pump, but turned out to be only a $10 rubber hose to replace).

- Vanagon, some type of plastic coolant distribution manifold with 4 hoses attached. Bought an aftermarket stainless steel part for $90. Evidently a known weak part.



Both were a tow home, start filling with water until I could spot the leak, and then repair. Then remove as much coolant as possible to refill properly with a good coolant / water mixture, properly bleed, etc.



It seems the next step is probably to put water (or coolant if you choose) in and see if you can spot the leak from above. Then have to jack it up, remove the pans, and fill until you can spot the leak.



Roland

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[Duckman]

I once had an occurence of rapid coolant explusion upon shutting down the engine after some spirited track time. It turned out to be a worn out coolant reservoir cap. One of the guys at the track had a spare and I'm still using it. Never had the problem again.

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[Scott Collins]

Check the short hoses around the HCV - even a small tear in either of those (on the underside, for instance, where you can't see it) will let the coolant fly everywhere - they are subjected to the heat of the exhaust manifold in addition to the coolant. Of course if you already checked these, then so much for the "easier" fix. Good luck.



Cheers!



-Scott



Had one of these go on me just a few miles down the road on my way to play golf. Nastly but unique smell of coolant being cooked off. I actually had a spare hose in my parts bin, drove home, swapped it out, added coolant and bled the system, and made the tee time. One of the few times I can say I actually "won" one. <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[flash]

if there is coolant on the header, but not at the heater control valve, i suspect the heater hose

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[Gentleman Driver]

[quote name='flash' post='64500' date='Dec 21 2008, 04:53 PM']if there is coolant on the header, but not at the heater control valve, i suspect the heater hose[/quote]

OK, is the heater hose what goes into the HCV?



I imagine much of this will be solved once I flush coolant through it again...



Thanks and MERRY CHRISTMAS!!!

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[xrad]

fill up the fluid with distilled H2o, and run the car standing still with the hood open to find the leak.

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[Gentleman Driver]

[quote name='xrad' post='64660' date='Dec 25 2008, 07:23 AM']fill up the fluid with distilled H2o, and run the car standing still with the hood open to find the leak.[/quote]

OK, finally got a jack and stands from my friend who was out of town and got out there to check out the issue... After 30 minutes of braving wind-swept rain and diminishing light to jack the car up (trying new methods mind you to see the best way...), and then removing the bottom plastic pan, I started to pour in distilled water to diagnose the problem.



Water immediately started flowing onto the ground so I jump underneath to see where it is coming from... had nothing, was just going everywhere! So I pour more in and then take a flashlight and look from the top. Low and behold it is indeed the Heater Control Valve where the water is flowing from! Needless to say I was kicking myself for spending all that time and effort getting the car in the air, especially because it is outside on asphalt.



SO, I should have heeded all of your advice and just poured water in to see if it was the HCV without all of the hassle...



Now, since I know what it is, where can I purchase the upgraded metal HCV?



Thanks again!

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[flash]

don't bother - it requires adaptation for the vacuum line, and is not a direct fit - however, if you install the new heat shield, you shouldn't have the problem again, since the heat from the exhaust manifold that caused it to fail is being significantly reduced

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[Gentleman Driver]

[quote name='flash' post='65085' date='Jan 4 2009, 05:55 PM']don't bother - it requires adaptation for the vacuum line, and is not a direct fit - however, if you install the new heat shield, you shouldn't have the problem again, since the heat from the exhaust manifold that caused it to fail is being significantly reduced[/quote]

OK, can you elaborate on the heat shield... (if it is better for me to search, just say so, but never heard of this).



<img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[flash]

lol - go to the rs barn site - you can see it there in the 968 products section

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[xrad]

Hmmm...should you get the metal or plastic version heater valve???

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[968Syncro]

[quote name='flash' post='65090' date='Jan 4 2009, 05:22 PM']lol - go to the rs barn site - you can see it there in the 968 products section[/quote]



So flash, this is the first time I looked at that part on the RS Barn site. In the description it says "This Heat Shield is similar in design to the one Porsche used on the Tiptronic cars, ..."



So I have a Tiptronic, 93, just looked, and there is no heat shield. I wonder if it was included in later tip cars, or some prior errant mechanic decided it would work well on one of his other cars <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" /> . (That is an errant mechanic besides me <img src="/forum/images/smilies/968/huh.gif" class="smilie" alt="" />) Any idea, should my car have this in place? I was also wondering what is different in this section of the engine bay that would have caused Porsche to decide a tip car should have a heat shield here vs a manual car... I didn't see anything... the ATF lines to the ATF cooler are on the other side of the engine. ?? Thanks!



Roland

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