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2006 PF SE Coolant purge head scratcher

Posted: Thu Sep 19, 2013 12:03 pm
by rannunziato
2006 PF SE 4.0L V6 4WD Auto 131K miles....So I had my rad flushed and filled. Now seems to purge coolant from overflow bottle randomly and routinely. Not sure what to make of it. Seems to occur when stopped and engine heat builds after driving for a while. Temp. gauge in normal range at all times...Drive for a while, pull into parking space or garage, and electric auxiliary fan kicks on and when I turn the truck off, the coolant bottle burps coolant, approx a pint or so. Was told several possible sources: stuck thermostat, fan clutch, H2O pump fins worn and not circulating coolant properly, and finally internal blockage of coolant channel in engine head. Would need to pull intake manif. and clear blockage manually.

Please advise,

06 PF coolant purge

Posted: Thu Sep 19, 2013 12:05 pm
by rannunziato
Oh, and btw had the system emptied and vacuumed tested and re-filled, holds vacuum and still have the problem. Not sure if it's air getting into the system somewhere or a pressure building and purging problem.

Posted: Thu Sep 19, 2013 12:56 pm
by eieio
my guess is that there is still air trapped somewhere in the system, possibly in the rear heater lines
try a forum search for the "burping" procedure with the front end of the truck elevated, and the front & rear heaters on full hot setting (for maximum coolant flow)

Posted: Thu Sep 19, 2013 1:07 pm
by rannunziato
We did that, elevated front end end while engine running with heat on, front and rear...still burps

Posted: Thu Sep 19, 2013 1:33 pm
by eieio
where is your coolant burping from?

Posted: Thu Sep 19, 2013 1:45 pm
by rannunziato
The over flow "bottle", not the radiator

Posted: Thu Sep 19, 2013 1:54 pm
by eieio
rannunziato wrote:The over flow "bottle", not the radiator
is it coming from the bottle overflow hose?

Posted: Thu Sep 19, 2013 2:49 pm
by rannunziato
Yes

Posted: Thu Sep 19, 2013 3:29 pm
by eieio
are you adjusting the coolant level to between the high and low marks, no more, no less?

Posted: Thu Sep 19, 2013 7:47 pm
by CPLTECH
Since this happened right after service, is it possible they switched caps?
The pressure cap belongs on the bottle, right?

Posted: Thu Sep 19, 2013 9:20 pm
by eieio
CPLTECH wrote:Since this happened right after service, is it possible they switched caps?
The pressure cap belongs on the bottle, right?
yes it does, good thought

Posted: Fri Sep 20, 2013 5:08 am
by rannunziato
Sorry for the delayed responses, Yes the levels were adjusted properly during servicing. Right now I have everything overfilled just to prevent overheating as a result of repeated purging. Seems to only occur when outside temp is elevated above 80 F and I get on the truck a little. When I put a load on the engine, going from point A to B without beating on the truck, when I come to a stop, aux fan kicks on, then coolant purge. I know that since the system is overfull at this point it's going to occur. I'm leaning towards the rear heater lines, as there is some discussion about leaks. My course of action is going to be; drain and vac down the system, replace thermo, (cheap and w/131k should be replaced anyway). Then drive and see what I get. If it continues, I'll have my guy check the rear lines (any suggestions on proper diagnostics would be appreciated). After that, if still no results, probably pull intake manif and look at coolant loops in head for gunk/blockage. The bitch of it all is I'm spending approx $300 per week chasing this gremlin down. Would love to approach from a scientific and educated pov. Also, The bottle cap does not have a pressure spring only the rad. Replaced rad cap and still no change....

Posted: Fri Sep 20, 2013 7:56 am
by eieio
rannunziato wrote: Also, The bottle cap does not have a pressure spring only the rad. Replaced rad cap and still no change....
methinks therein lies the problem! :)
the cap with the spring-loaded plunger belongs on the bottle, not the radiator
the bottle cap needs the spring loaded plunger to keep coolant in until the pressure exceeds that of the caps' rating
at that point, the expanding coolant can escape by raising the plunger off of its' sealing surface of the bottle
GOOD JOB CPLTECH! :wink:

Posted: Fri Sep 20, 2013 11:14 am
by rannunziato
Boy, that would sure get my shorts in a bunch.....I paid a pile of cash chasing this issue only to discover mechanic error. Are you sure the rad doesn't get a spring plunger and the bottle does? I am concerned about damage to the system if the rad doesn't have a relief valve....I still have the Auto Zone replacement cap w/plunger. What if I leave the OEM cap on the rad., and put the AZ cap w/plunger on the bottle? Would that work?

Posted: Fri Sep 20, 2013 12:07 pm
by disallow
confirmed. Rad cap with spring on bottle, no spring on rad.