Porsche Enthusiasts Club Forum

It is currently Thu Mar 28, 2024 11:37 pm
Classic Line Insurance


All times are UTC [ DST ]




Post new topic Reply to topic  [ 9 posts ] 
Author Message
 Post subject: 986 2.7 Coolant Boiling Over
PostPosted: Mon Dec 04, 2017 2:27 pm 
Offline

Joined: Mon Jun 23, 2008 2:27 pm
Posts: 934
Location: Oxford
TIPEC membership: 5218
I picked up a 02 986 2.7 that needed a new water pump recently. I've now changed the pump for a piersburg one but I'm still getting some issues when in traffic.

When driving along normally it's absolutely fine however when sat in traffic things start going a bit wrong. I can hear the radiator fans come on briefly which is fine. The temp needle never strays much above the 80 mark however when sitting in traffic for too long I'll hear the fan in the engine bay kick in, smell the unmistakeable smell of hot coolant and eventually I'll be leaving a trail of the stuff behind me as it overflows out of the coolant tank.

I've just ordered a new cap in the hope that that's going to fix the problem but does anybody have any other ideas? I've tried bleeding the system repeatedly but it never seems to make much difference. The thing that's confusing me the most if that the engine doesn't overheat at any point. I'd be expecting the temp to be through the roof for the coolant to overflow.

I haven't had the car for long and don't have a garage handy in order to do too much investigation (especially not in this weather!).

_________________
1983 Porsche 944 - Ongoing project/problem child
1988 Porsche 944S - Sold!
2002 Boxster 2.7 - Daily Driver


Top
 Profile  
Reply with quote  
 Post subject: Re: 986 2.7 Coolant Boiling Over
PostPosted: Mon Dec 04, 2017 2:48 pm 
Offline
Site Admin
Site Admin

Joined: Thu Jan 01, 1970 1:00 am
Posts: 5523
Location: Rochester, Kent
TIPEC membership: 911
Cracked expansion tank would be my guess. They open up when they get hot.

_________________
Kent & South East London R.O

Join the Club

Silver 1989 911 Speedster
Midnight Blue 2004 996 C4S Cab
Tahoe Blue 1990 964 C2
Zenith Blue 1998 BoxsterSold
Guards Red 1992 944 S2 Cab gone but not forgotten
Mediterranean Blue BMW 530e


Top
 Profile  
Reply with quote  
 Post subject: Re: 986 2.7 Coolant Boiling Over
PostPosted: Mon Dec 04, 2017 3:20 pm 
Offline

Joined: Mon Jun 23, 2008 2:27 pm
Posts: 934
Location: Oxford
TIPEC membership: 5218
I'm hoping not purely due to the cost of a new one. Would be cheaper to finally replace the knackered wheel bearing on the 944 and use that for a bit if that's the case.

Need to get around to digging everything out of the boot but won't be seeing the car in daylight for a few weeks sadly.

_________________
1983 Porsche 944 - Ongoing project/problem child
1988 Porsche 944S - Sold!
2002 Boxster 2.7 - Daily Driver


Top
 Profile  
Reply with quote  
 Post subject: Re: 986 2.7 Coolant Boiling Over
PostPosted: Tue Dec 05, 2017 3:28 pm 
Offline
Moderator
Moderator
User avatar

Joined: Sun Nov 04, 2007 8:43 pm
Posts: 12645
Location: Chatham, Kent
TIPEC membership: 4190
Needs the fans and resistors investigated. Both can be an issue. However when mine used to brew up it was because the DME was knackered and not triggering the fans on.
If it has a/c switch that on and see if the fans at the front run at top speed, they should.
Other options are the header tank as Sean said. A pig to swap.

_________________
Jim

http://tipec.net/region_southeastlondon.php

2018 Mitsubishi Outlander PHEV
2005 Porsche Cayenne S Now sold!
2000 Jeep Grand Cherokee Now sold!
2010 Mazda MX5 Mk3.5 2.0 Sport Tech
2000 Porsche Boxster S SOLD!
1987 Porsche 944 2.5


Top
 Profile  
Reply with quote  
 Post subject: Re: 986 2.7 Coolant Boiling Over
PostPosted: Thu Dec 07, 2017 12:37 am 
Offline

Joined: Mon Jun 23, 2008 2:27 pm
Posts: 934
Location: Oxford
TIPEC membership: 5218
After the last incident I parked it on a bloody steep hill and went for another bleeding of the system. I've not had any issues since but I ordered a new cap for the hell of it. Got the cap tonight and have been running around town, sat around idling, going for a bit of a hoon then sitting around a bit more. All seems absolutely fine.

If anything the fans have stayed on for longer than they have before and the engine bay fan didn't turn on at all.

Looks like it was probably the bleeding but changing the cap can't have hurt. I did have the .01 but now have .04.

I miss having an MR2. When that needed bleeding you knew about it because it sounded like you were driving over a mine field and to bleed it you opened a couple of valves and attached the Toyota supplied hose to each one. At least the Boxster has more grunt, a better sound, and more creature comforts.

_________________
1983 Porsche 944 - Ongoing project/problem child
1988 Porsche 944S - Sold!
2002 Boxster 2.7 - Daily Driver


Top
 Profile  
Reply with quote  
 Post subject: Re: 986 2.7 Coolant Boiling Over
PostPosted: Thu Dec 07, 2017 8:54 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Nov 04, 2007 8:43 pm
Posts: 12645
Location: Chatham, Kent
TIPEC membership: 4190
The caps were an issue, hence the different revisions. Surprised that there are any old ones left installed. Glad you'be sorted it though

_________________
Jim

http://tipec.net/region_southeastlondon.php

2018 Mitsubishi Outlander PHEV
2005 Porsche Cayenne S Now sold!
2000 Jeep Grand Cherokee Now sold!
2010 Mazda MX5 Mk3.5 2.0 Sport Tech
2000 Porsche Boxster S SOLD!
1987 Porsche 944 2.5


Top
 Profile  
Reply with quote  
 Post subject: Re: 986 2.7 Coolant Boiling Over
PostPosted: Thu Dec 07, 2017 4:33 pm 
Offline
Site Admin
Site Admin

Joined: Thu Jan 01, 1970 1:00 am
Posts: 5523
Location: Rochester, Kent
TIPEC membership: 911
Well done, pleased that it is sorted.

_________________
Kent & South East London R.O

Join the Club

Silver 1989 911 Speedster
Midnight Blue 2004 996 C4S Cab
Tahoe Blue 1990 964 C2
Zenith Blue 1998 BoxsterSold
Guards Red 1992 944 S2 Cab gone but not forgotten
Mediterranean Blue BMW 530e


Top
 Profile  
Reply with quote  
 Post subject: Re: 986 2.7 Coolant Boiling Over
PostPosted: Sat Dec 09, 2017 10:17 pm 
Offline
Moderator
Moderator

Joined: Wed Nov 07, 2007 12:00 pm
Posts: 1510
Location: Kingston upon thames
Replacement cap sorted mine too

_________________
Cayenne S 4.5 06 Basalt Black
924S 87 Guards Red
924S 87 Alpine White Sold
Boxster 2.7 Silver 00 Sold
Boxster S Meridian 01 Sold
928 S2 Prussian Blue 86 Sold
993 C4 Arena Red 97 Sold


Top
 Profile  
Reply with quote  
 Post subject: Re: 986 2.7 Coolant Boiling Over
PostPosted: Mon Jan 15, 2018 2:21 pm 
Offline

Joined: Mon Jun 23, 2008 2:27 pm
Posts: 934
Location: Oxford
TIPEC membership: 5218
Just a quick update on this. I replaced the coolant cap and also spent a while on a rather steep hill bleeding the system further and all seems well now.

Well apart from the poor people who live on that hill, I did the same for my 944 the weekend after so they must love me now :D

_________________
1983 Porsche 944 - Ongoing project/problem child
1988 Porsche 944S - Sold!
2002 Boxster 2.7 - Daily Driver


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group