QuestionQUESTION: I've been having some difficulties with overheating. First of all in the Fall 07
a "Y" shaped pipe corroded causing loss of fluids. This was repaired but
shortly afterwards the car began to overheat. I could regulate and keep from
overheating as long as my heater was turned on full blast. Took to garage to
have a new thermostat put in. Day after I picked it up...same problem
occurred, overheated while driving so had to turn on the heater again. Please
note: The car did not seem to overheat when sitting idle. Only when driving.
I have now been told its likely the water pump and timing belt. Others are
suggesting the head gasket. There does not appear to be any residue
appearing in my coolant and I've also taken it for a test at a radiator shop to
check for hydrocarbons to rule out head gasket. Garage (not radiator shop) is
saying that this test isn't 100%. Is this true? Or can I confidently rule out the
head gasket as the problem?
With it blowing hot air and not cold could this still mean water pump? It has
been doing this for 3 mths now with no resolution. Today (2 days before its
scheduled with the garage) it suddenly began to blow cold air and temp
gauge went up. It left on a flatbed :)
I would appreciate your opinion on this. 4 out of 5 say water pump and
timing belt.
I look forward to your response.
ANSWER: Hi Linda,
I would not conclude it was the waterump if it is not making noise and not leaking (other than a slight weeping from the drain hole on the underside, which is normal).
The timing belt is NOT relevant to the problem as it doesn't drive the water pump at all, has nothing to do with the cooling system. It should only be inspected to see if it is showing signs of wear as a separate issue. The belt should be considered for replacement at 100K miles, but you can inspect it at that time and decide.
If you aren't loosing coolant noticeably, and you don't see excessive white smoke when you start it up from cold coming out the tail pipe, and the radiator shop found no trace of exhaust gases, and you don't hear bubbling internal and blowing of steam out of the overflow bottle early after starting, then none of the signs of a head gasket leak are present.
I would note that this cooling system has a special tool and filling procedure requirement to avoid air being trapped inside of it, which may well cause your problem. If the shop isn't aware of it and doesn't have the tool/filler bottle then I would find a place that does (maybe a dealer?).
I would check that both side manifolds of the radiator feel about equally warm as a check for the cross flow situation thru the readiator.
The air trapped issue may be the most important thing to be sure is not the cause. Let me know if I have misinterpreted the situation but that is how I see it. Don't opt for any costly repair until the proof is there.
Roland
---------- FOLLOW-UP ----------
QUESTION: Since my initial questions the following has taken place...
Garage has bled the air out again, topped up coolant, oil. Overheating still.
Although I changed thermostat a few months ago trying to resolve the
problem he suggested going back to the thermostat again. Overheats.
4 out of 5 people said water pump (impeller problem possibly). I just received
a call and mechanic says there is nothing wrong with my water pump. Car is
at 106kms so I am going to proceed and have them change the timing belt
while he's working in there. He noticed I need a new air conditioning belt.
Next step he suggests replacing the rad. All the horror stories I'm
reading...replacing this part, that part with no success I'm getting concerned!
I've also contacted the dealer. They say they've rarely changed a rad on a
3.5L so they don't believe that would be the cause of the circulation problem.
Only other part they referred to is a "jet" oriface (?). This jet could be
plugged.
I know you said don't opt for costly repairs until the proof is there...that's
exactly what is happening and I'm not sure where to turn or what to do. Due
to the design of this engine everything seems to be labour-intensive even to
eliminate the possibilities.
Any other suggestions? This single mom needs help as its getting very costly
:)
ANSWER: Hi Linda,
It would possibly be helpful if you could tell me the symptoms of "overheat". What happens exactly? and does it boil over? and how soon after starting the engine, and under what weather and driving conditions?
It wasn't clear if the thermostat was replaced again, was it?
I wonder about the "Y" tube that was replaced, but I don't know which one that was. Its being corroded may suggest something going on where it attached that is impeding the flow of coolant.
Has anyone tried flushing out the cooling system with system cleaner?
Have you checked to see if the air flow thru the radaiator is open fully (place a light behind the radiator assembly and look thru the grille to view the air fin openings to be open or clogged.
Those are my suggestions before moving ahead on more "jobs". Answers to the above might also help me.
Roland
---------- FOLLOW-UP ----------
QUESTION: Hi Roland,
Thanks for responding so quickly. You'll have to bear with me since I'm not very
knowledgeable in this field.
I can only drive maybe 1-2kms and the gauge begins to rise. If I don't put the
heat/fan on high the gauge will continue to climb. With the heater blowing it can be
regulated to stay at the 1/2 way mark on the gauge. It has not "boiled" over.
Weather conditions don't seem to alter the symptoms too much. Probably a little
quicker now than when the snow/cold were here.
As far as the "Y" shaped pipe that corroded - all I know is the dealer's p/n
4767150AC. Think it was located in the area near the thermostat (but not sure).
Thermostat has indeed been changed a second time.
System flush - don't believe that has happened. Only air bleed process.
As far as the radiator I don't know if the mechanic has checked the air fin openings.
He also doesn't believe its head gasket.
Do you have any information on the "jet" they've referred to? Dealer suggests
checking that out after the rad. Is it associated with the head? If so, I would expect
I'm looking at major $$$$$....
AnswerHi Linda,
Thanks for the evaluation, nomination, and comment. Final question, for now, were both radiator fans running on high speed when it boiled over while idling? If not, then that would be a very relevant cause of the problem. Other than that, keep observing, check that air passageway question (the passageways may be blocked with leaves or dirt). I'm in the SF Bay area of Northern California.
Roland
