Pressure cap diagnosis - Defender Source
Defender Source  

Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions


Reply
 
Thread Tools
  #1  
Old May 10th, 2015, 07:07 PM
Overlander's Avatar
Overlander
Status: Offline
mark kellgren
in between D's in an 04 D2
Member
 
Join Date: Mar 2006
Location: Charlotte, NC
Posts: 6,531
Registry
Pressure cap diagnosis

I've been having overheat issues that are symptomatic of air in the system/air locks with the temps normal for a while than a sudden spike. Had it diagnosed locally at a shop with diesel and rover experience, and they said it just needed to be burped more. Have gone through air bleed cycles several times and had another major over heat. Everytime i think this system has been filled finally , I'll end up a day or two later with another overheat (and immediate pullover-rest). After each overheat, then next day after a full cooldown, the radiator tank it low and the expansion tank is high.

shop confirmed t-stat was working fine and said they don't think there's an issue with the headgasket as no gas has been observed in the coolant with engine running.

After longer runs where the engine gets good an warm, when I stop the engine and get out, I can hear a slight hissing from the expansion tank and sometimes the pressure cap will purge some fluid.

I just replaced the pressure cap with a new one, and will test drive it tomorrow. But for a properly operating 300 tdi, how do you know when the system has been bled properly? For a completely bled system, would the t-stat fill plug always be completely full when removed cold, or would there be some air in it?

My understanding is that the fill line in the expansion tank is the same level as the radiator fill plug. What would cause the radiator level to drop and the expansion tank level to rise?

Also, if my old pressure cap didn't seal well on the threads under pressure, what would be the symptoms observed from that?

I'm starting to lose confidence in this 2.8 engine. It's been a run of trouble.
__________________
Mark Kellgren
KM4BOR

ISIL and al qaeda can go F*ck themselves...
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old May 10th, 2015, 07:20 PM
Jymmiejamz's Avatar
Jymmiejamz
Status: Offline
Jimmy
1995 D90 SW #365
Member
 
Join Date: Sep 2010
Location: Brooklyn, NY
Posts: 3,468
Registry
Sounds more like a head gasket, cracked block, or cracked cylinder head. The hissing from the cap is probably due to the system being over pressurised. I would recommend getting a block test kit to see if you are getting any combustion gases in the cooling system. They don't always detect combustion gases, but if it does, then you know there is a big problem. How long does it take to overheat?
__________________
Car Camping Collective founding member and Treasurer
Reply With Quote
  #3  
Old May 10th, 2015, 07:30 PM
leastonce's Avatar
leastonce
Status: Offline
Jason England
D-90 White 95 SW #65
Site Team
 
Join Date: Jul 2009
Location: NYC
Posts: 6,078
Registry
i couldn't detect combustion gases with one of those kits ... you might have better luck.

can you have the truck filled with coolant under vacuum ... that would eliminate any burping issues.

What would cause the radiator level to drop and the expansion tank level to rise? ... excess pressure would
__________________
Quote:
Soapy water / KY jelly, etc. is is basically a must. Yes, good idea to remove trim panels - only takes 5 more minutes to do so.
Car Camping Collective founding member and Chief Executive Officer
Cat Camping Collective founding member and Chief Executive Officer
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old May 10th, 2015, 07:49 PM
Overlander's Avatar
Overlander
Status: Offline
mark kellgren
in between D's in an 04 D2
Member
 
Join Date: Mar 2006
Location: Charlotte, NC
Posts: 6,531
Registry
Quote:
Originally Posted by Jymmiejamz View Post
Sounds more like a head gasket, cracked block, or cracked cylinder head. The hissing from the cap is probably due to the system being over pressurised. I would recommend getting a block test kit to see if you are getting any combustion gases in the cooling system. They don't always detect combustion gases, but if it does, then you know there is a big problem. How long does it take to overheat?
overheat is very random. it can go a few days sometimes. It's going back to the shop tuesday for further diagnosis.

I did the headgasket in the fall. had the head shaved (had no warp) and pressure tested. I've did a pressure test today and the system was able to hold at 13psi for an hour.
__________________
Mark Kellgren
KM4BOR

ISIL and al qaeda can go F*ck themselves...
Reply With Quote
Reply

Lower Navigation
Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
clutch problem diagnosis help... bharris Defender Technical Discussions 18 November 14th, 2011 04:42 PM
need help with diagnosis of 3.9 fuel problem Art Vigil Misc. Chit-Chat 15 July 7th, 2010 01:07 AM
Trail break diagnosis phoenix37 Defender Technical Discussions 15 July 27th, 2009 02:41 PM
OBD2 - P0420 Diagnosis pcscharfe Defender Technical Discussions 1 January 12th, 2008 02:28 PM
Clutch issue? Help with diagnosis..... Hans Defender Technical Discussions 13 December 18th, 2005 05:19 PM


All times are GMT -5. The time now is 11:16 AM.


Copyright