coolant overflow - Alfa Romeo Bulletin Board & Forums

  #1 (permalink)  
Old 06-02-2011, 10:54 AM
Registered User
Gold Subscriber
 
Join Date: Aug 2007
Posts: 161
coolant overflow

My 91L has a sudden coolant malady that I can't quite figure out. When hot the reservoir overflows through the sensor cap. I'm not overfilling the reservoir; when cold it's at the minimum level.

I first noticed the problem a few days ago when I parked the car for a few hours after a long drive. I returned to the car, started her up and saw that the coolant warning light was on. I also noticed coolant on the street. When I opened the hood and checked the reservoir it was almost empty. There were no signs of leakage except around the top of the tank near the caps. This morning, for an experiment, I drove the car until hot, parked her, observed the coolant coming out through the sensor cap and then opened the filler cap (carefully, of course) where additional overflow emerged. I then milked the top radiator hose (leading to the thermostat). This sent up little puffs of steam from the reservoir. The coolant level declined with each squeeze of the hose until it was back down to a normal level.

There is no mayonnaise inside the oil filler cap or dipstick and none in the reservoir. I replaced the thermostat a few months ago.

Anybody have any idea what's going on?

Mac D
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-02-2011, 03:18 PM
multicam's Avatar
Registered User
 
Join Date: Nov 2005
Location: CT
Posts: 856
Were you in stop and go traffic? What was the ambient temperature outside?

Could be your relief valve on the coolant tank not keeping the proper pressure i the system and thus lowering the boiling point and hense your overflow.
Could be a blown headgasket. Check the coolant for oil residue

Could be a tired old radiator, check the fins for flaking , if the flaking is greater than 20% of the fins then the radiator is probably not cooling down the engine very well, hense the boil over.
__________________
1994 164 LS 5 Speed
1960 Giulietta Spider
1959 Giulietta Sprint

1965 Giulia Spider [parts car now]
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-02-2011, 03:51 PM
racingswim2006's Avatar
Registered User
 
Join Date: Apr 2006
Location: SE Michigan
Posts: 2,774
Check/replace cap.
__________________
Rob
Alfas first, then everything else.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-02-2011, 04:53 PM
Alfisto Steve's Avatar
Senior Member
Platinum Subscriber
 
Join Date: Dec 2003
Location: VB, VA
Posts: 20,642
Does your cooling fan run on low speed system or just high speed? What kind of reading are yoiu getting on temp gauge? Is car stock cooling configuration?

Cap can be bad and little coolant can bypass but if sensor float cap leaking sure it can be bad, too or have bad gasket but cap and sensor should not be bypassing if system is operating correctly.
__________________
Ciao, Alfisto Steve
Virginia Beach, VA
AROC 164 Tech Advisor
http://www.aroc-usa.org/ click on tech advisors to contact me by email for tech advice or use this AlfaBB 164 section or an alfabb Private Mail.

Daily drivers: USA models - 91 164L w/AT "Black Beauty I" ALFA4ME; 91 164S Black Beauty II ALFALFA

SOLD MY91 "Bianco" 164B 5-speed [My Originale], ALFISTO Movin On!
Also gone are Old Blue 91 164L, Rosso1 93 164L, Rosso2 91 164S; QS2 164L

Daughter's current ride: Her Granddads 2002 Ford Taurus

Current Car hauler and Parts chaser : 2000 Dodge Ram PU 5.2L V-8

"A day without an Alfa whine is like a day without sunshine"
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-02-2011, 09:46 PM
Registered User
Gold Subscriber
 
Join Date: Aug 2007
Posts: 161
The thing is, the system is not boiling over. The fan is working properly -- low and high speeds. The temperature gauge shows everything within proper range. And the coolant is not steaming or boiling out when I open the cap.

I first noticed the low coolant level following a long freeway drive (no stop and go) and after the car had sat parked for a couple of hours. I now see the problem after driving around in regular traffic. There is no visible indication of a blown head gasket. No mayo in the oil; no oil scum in the reservoir. Nor do I see any bubbles in the reservoir when I idle with the cap off.

Could there be a blockage somewhere? Why would the coolant level go down when I milk the upper radiator hose? It's a mystery. Where's Agatha Christie when you need her?

Mac D
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-03-2011, 06:05 AM
Alfisto Steve's Avatar
Senior Member
Platinum Subscriber
 
Join Date: Dec 2003
Location: VB, VA
Posts: 20,642
Well maybe one of two things or both. Say system working as normal with good fan system, good engine thermostat and radiator OK.

Coolant cap relief valve stuck so thermal heat after shut down ends up forcing coolant by seal around sensor float shaft is original style with brass rod and "wine cork" style float or seal under retainer nut cracked or nut loose.

New style sensor floats a sensor float around a plastic support.

Inspect retainer nut gasket and if good try tightening sensor retainer nut on tank and if that doesn't stop it leak.

Coolant tank cap maybe OK if seals bad in sensor.
__________________
Ciao, Alfisto Steve
Virginia Beach, VA
AROC 164 Tech Advisor
http://www.aroc-usa.org/ click on tech advisors to contact me by email for tech advice or use this AlfaBB 164 section or an alfabb Private Mail.

Daily drivers: USA models - 91 164L w/AT "Black Beauty I" ALFA4ME; 91 164S Black Beauty II ALFALFA

SOLD MY91 "Bianco" 164B 5-speed [My Originale], ALFISTO Movin On!
Also gone are Old Blue 91 164L, Rosso1 93 164L, Rosso2 91 164S; QS2 164L

Daughter's current ride: Her Granddads 2002 Ford Taurus

Current Car hauler and Parts chaser : 2000 Dodge Ram PU 5.2L V-8

"A day without an Alfa whine is like a day without sunshine"
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-03-2011, 11:30 AM
Registered User
Gold Subscriber
 
Join Date: Aug 2007
Posts: 161
Just for the heck of it, I replaced my fill cap with a used one I had on hand. Took the car for a spin -- same trouble: I got home and found coolant coming out through the sensor cap.

So I took off the fill cap in order to observe the coolant level as I milked the top radiator hose. I could see the level sink back down. I kept the cap off and ran the car at fast idle in the driveway until she was as hot as the fan would allow; the level stayed down. But when I shut off the car the level rose back to almost an overflow. I started the car again. The level dropped. I shut it off again. This time the level stayed down.

What's interesting is that the coolant reservoir was almost emptied the first time this problem occurred -- as though something had been pushing the coolant out. My first suspect was a leaking head gasket blowing pressure into the system. But as I noted before, there is no other evidence of a bad gasket. Also, it seems that the overflow happens after the engine is stopped -- just as it did the first time.

Yikes!
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 06-03-2011, 12:37 PM
goats's Avatar
Registered User
 
Join Date: Jul 2006
Location: san diego CA
Posts: 2,590
try bleeding the tstat

Given all the symptoms I might suspect a big ole air pocket somewhere given that what youve already tried
__________________
goats

74 GTV with 10548's and Ingram pump --speedo been around at least twice -- [B]needs new oil rings[/B]!
1995 LS Q runners Auto Green/tan [B]230K[/B] 100% LCD paint absolutely SHOT!
1995 LS 5 speed Green /tan 48K Q runners squadra chip 100 % LCD -- nice tight car
Misc parts laying around for 24V and 2Liter- always need more it seems
2004 Tacoma 4 door TRD (wifes car/kid hauler)- 172K
Mission Vsi, Mission Mod 2, - 20+ years of hockey on these!
radio flyer- rusty from disuse!
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 06-03-2011, 01:24 PM
Registered User
Gold Subscriber
 
Join Date: Aug 2007
Posts: 161
Goats:

Yeah, I was thinking of something like that. The air gets hot, expands and pushes the coolant out. But it would have to be a big pocket in order to almost displace the entire contents of the reservoir, and it would have to be trapped somewhere or else it would bubble out through the reservoir coolant. How do you get rid of such a gremlin if it is indeed the cause?

Another development: since changing filling caps it appears that the high-speed fan only is coming on. No low-speed. The temperature gauge is averaging higher than usual and when the fan finally does come on there's a big jump in the ammeter and a sensation that the fan is lurching into action.

Does that add anything to the equation?

Mac D
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 06-03-2011, 01:29 PM
goats's Avatar
Registered User
 
Join Date: Jul 2006
Location: san diego CA
Posts: 2,590
yeah you might have found it!

does the fan spin freely by hand? Even though your fan may be coming on, I wonder if its spinning at the designed RPM range- if its binding up at all, that might explain this whole thing

OR, you could have a bad/dirty connection to the fan that is showing up as a high resistance to the fan motor, which in turn will make the fan run slower. Fan relays are a suspect, but first I would check fan mechanical condition and connection to the fan motor
__________________
goats

74 GTV with 10548's and Ingram pump --speedo been around at least twice -- [B]needs new oil rings[/B]!
1995 LS Q runners Auto Green/tan [B]230K[/B] 100% LCD paint absolutely SHOT!
1995 LS 5 speed Green /tan 48K Q runners squadra chip 100 % LCD -- nice tight car
Misc parts laying around for 24V and 2Liter- always need more it seems
2004 Tacoma 4 door TRD (wifes car/kid hauler)- 172K
Mission Vsi, Mission Mod 2, - 20+ years of hockey on these!
radio flyer- rusty from disuse!
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 06-03-2011, 05:56 PM
Alfisto Steve's Avatar
Senior Member
Platinum Subscriber
 
Join Date: Dec 2003
Location: VB, VA
Posts: 20,642
Quote:
Originally Posted by Mac D View Post
Goats:

Yeah, I was thinking of something like that. The air gets hot, expands and pushes the coolant out. But it would have to be a big pocket in order to almost displace the entire contents of the reservoir, and it would have to be trapped somewhere or else it would bubble out through the reservoir coolant. How do you get rid of such a gremlin if it is indeed the cause?

Another development: since changing filling caps it appears that the high-speed fan only is coming on. No low-speed. The temperature gauge is averaging higher than usual and when the fan finally does come on there's a big jump in the ammeter and a sensation that the fan is lurching into action.

Does that add anything to the equation?

Mac D
Yes it does. Check fan resistor in radiator fan shroud it maybe bad. Try bypassing it by hooking dark blue and brown wire to it together and see if you now get a higher fan speed at a lower temperature.
__________________
Ciao, Alfisto Steve
Virginia Beach, VA
AROC 164 Tech Advisor
http://www.aroc-usa.org/ click on tech advisors to contact me by email for tech advice or use this AlfaBB 164 section or an alfabb Private Mail.

Daily drivers: USA models - 91 164L w/AT "Black Beauty I" ALFA4ME; 91 164S Black Beauty II ALFALFA

SOLD MY91 "Bianco" 164B 5-speed [My Originale], ALFISTO Movin On!
Also gone are Old Blue 91 164L, Rosso1 93 164L, Rosso2 91 164S; QS2 164L

Daughter's current ride: Her Granddads 2002 Ford Taurus

Current Car hauler and Parts chaser : 2000 Dodge Ram PU 5.2L V-8

"A day without an Alfa whine is like a day without sunshine"
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 06-04-2011, 10:53 AM
Registered User
Gold Subscriber
 
Join Date: Aug 2007
Posts: 161
Thanks, guys. I'll follow your suggestions in the next couple of days and post the results.

Mac D
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 06-04-2011, 01:36 PM
Registered User
Gold Subscriber
 
Join Date: Aug 2007
Posts: 161
I'm baaaack...

Okay, I replaced the coolant level sensor with a unit from an old reservoir. So far, no overflow.

But I'm having trouble with the low-fan speed by-pass. I don't have wires that match your description, Steve. I have red, white and black wires going into the thermal switch. At one time, I knew which was the power supply wire and which belonged to the low and high-speed systems. If I still knew, which I don't, I figure I'd be able to switch the positions of the low and high-speed wires, allowing the high-speed system to activate at the lower system temperature. Am I right? And if so, which wire is the power supply wire?

Mac D
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 06-04-2011, 02:33 PM
Registered User
Gold Subscriber
 
Join Date: Aug 2007
Posts: 161
Oh wait, Steve... You're talking about the wires going into the resistor, not the thermal switch. However, wouldn't it be simpler to reposition the switch wires to test the system? There's less to remove, etc...

Mac D
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 06-04-2011, 04:11 PM
Del Del is offline
Senior Member
Gold Subscriber
 
Join Date: May 2005
Location: seattle
Posts: 7,105
Steve wants to you to bypass the low speed resistor to be able to see if it is faulty. If the rest of the circuit is ok you will get a high speed fan when the thermal switch trips at the lower temperature setting, and of course, you will still get the high speed fan at the high temperature setting (of the thermal switch).

If the low speed fan thermal switch instead is faulty, you will get nothing for the low speed setting, and the high speed fan setting will work, or nothing will work as well at the high temp setting if that part of the switch is faulty as well.

Nothing to remove, just jumper wire the two wires together when they are removed from the resistor. Easy to reach.
__________________
Del

Seattle

89 Milano
91 164S
94 164LS (Q)
72 Morgan 27

Last edited by Del; 06-04-2011 at 04:13 PM.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
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.



Thread Tools
Display Modes

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 Off
Pingbacks are Off
Refbacks are Off










Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2002-2011 AlfaBB.com All Rights Reserved.



SEO by vBSEO 3.3.2