pontiac under pressure - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 03-25-2002, 11:34 AM
New Member
 
Join Date: Oct 2001
Location: panama city
Posts: 13
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post pontiac under pressure

Equipment
fresh 455 60 over poncho, E-heads from Butler boys using thier head gaskets, new desert cooler copper rad, new and tested thermostat trie dd, new flow kooler water pump, new heater core, new hoses and belts, tried new 13 lbs and 16 lbs rad caps, no difference, 1 qt overflow can, water wetter, 50/50 antifreeze.electric fan in front of rad pushing towards engine, 15 inch flex on engine side(i know its not real efficent mostly for looks)The temp of the lower rad hose is 120 when the upper is 190 so I feel the rad is cooling ok, (opinions welcome here folks, is 120 degree water going into the block cool enuff?)
The plugs do not indicate a lean condition and I have tried varying the timing with little effect overall
Problem
At first it was overheating as the engine was getting its first 100 miles, 210-220 degrees
Now it will run 180-195 but heres where it gets bizarre.... as you let off the throttle to slow for a red lite, (at 185 or hotter) the overflow can sends a giant stream of coolant out the vent hole (like my Great Dane taking a pee)The pressure seems excessive and eventually this makes the coolant level low and the temp climbs.I am totally missing the connection between the de-acceleration and the spewing... the different pressure rated caps do not change anything.
at this point any ideas would be helpful and greatly appreciated
Thanxx
rob

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-25-2002, 01:04 PM
4 Jaw Chuck's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Mar 2002
Location: Manitoba, Canada
Age: 46
Posts: 4,974
Wiki Edits: 0

Thanks: 2
Thanked 89 Times in 72 Posts
Post

I have had caps that were grooved from age that did not fit tightly when turned down. I have also had rads that had deeper pockets where the cap sits so it did not seal properly. Just last week I repaired a customer car (98 Jeep) that had a rad cap that was only sealing if it was put on a certain way. I suggest you try a rubber disc cut out of inner tube and put that under the cap and see if it seals then, if it works then try going up to a 21 pound cap. Measure from the flange edge to the sealing edge with a vernier and then measure the rad spout, it should compress the inner sealing gasket at least 0.015".
__________________
Outlawed tunes from outlawed pipes
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-25-2002, 02:52 PM
dmorris1200's Avatar
doesn't play well with others
 
Last photo:
Join Date: Feb 2002
Location: Maine
Age: 49
Posts: 1,834
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Well I wish I had a good idea for you but can't think of anything at the moment. One thing that did come to mind (weather it relates or not,don't know) is you mentioned the relationship between decelleration and spewing. I know that when we burp a cooling system, after filling it, to get the air out we bring up the rpm's for a bit to build pressure in the block then release to idle to force t-stat to open quicker. If you hold the rpm's up too long and there's still air in the system as soon as the rpm's drop the pressure shoots coolant out of the radiator like a fire hydrant. Don't know if something could be causing this effect in your car but figured I'd mention it.
__________________
BUILT FORD TOUGH
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-25-2002, 03:03 PM
Member
 
Join Date: Nov 2001
Location: Livingston, Montana
Posts: 67
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

You did not say what your thermostat was rated at
195 degrees is what I would use also what is the year of your motor?1973 and on had EGR-valves, and the heads and intake for same year motor? most will all bolt-up but. Are you using a spacer between your water pump and radiator/ should be 2-inch spacer and do you have a schroud? all add up
If your in a high humity area(like Iowa) tourque your heads 20lbs more don't want a blown head gasket from overheating.Also get it up to temp without cap on be sure all air out of system.Is your new rad.have in and out in original location?

[ March 25, 2002: Message edited by: Pontiacman ]</p>
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 03-25-2002, 03:16 PM
Member
 
Join Date: Mar 2002
Location: little rock,ark.
Posts: 123
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

parrothead69,howdy!only a month ago i got my sons 89 chevy p.u. back from the frame shop[bent bad] and when went to reassemble the front end[we had torn it down,fendersgrillbumperetc.,in order to assess damage and save some dough]icould'nt find the radiator cap.so naturally a quick run to the local auto parts store was next.listen guy!same symptons the new cap was not sealing, the length of the cap while uncompressed [is that a word?]was too short so when i screwed it on it was not touching the shoulder of the rad. neck where it seals!my son went through the old part bin we keep and found an old cap of same locking ears size,everything hunky-dory now.a friend experienced the same thing when trying to use a new cap fom the same "discount' parts store.hope this helps ,jimm
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-26-2002, 09:02 AM
New Member
 
Join Date: Oct 2001
Location: panama city
Posts: 13
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

thanxx for the help everyone I am still trying stuff
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 07:27 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.