Have you experienced this in your S Type?
#1
Have you experienced this in your S Type?
Or for that matter, any of the more modern jags.
The coolant Temp guage goes to the center position fairly quickly and stays there, but every once in a while, I'll see the needle swing towards the 3/4 mark (halfway between center and Red)...then after a couple minutes, it will go back to center.
Now I've checked the coolant level and its fine, it also does not appear to have particulates or sludge.
The electric fan kicks on as it should. It is also running for a period of time after I shut the car off.
What I am thinking is either I have air in the system from the previous owner not having it properly filled/bled, AND/OR, I have a failing thermostat.
I called the Seattle Jag service center, but the conversation I had with the service advisor left me still with questions. Not that I question her knowledge, but it seems that "maybe" she didn't have a firm grasp on her technical skills.
I was told this is normal for Jags, to have the temp swings, ie the thermostat stays closed during normal temps, then when the coolant reaches a certain temp, the thermo opens up again/fan kicks on, temp needle goes back to center, thermo closes again, when temp rises, thermo opens again....rinse repeat.
I've owned many a car, and worked on them all
I've never heard of this as being "normal" behavior
My experience, is that the thermo will open once the engine temp reaches 185 degrees or so (depends on the thermo) and then it modulates how open/closed it is to keep the temp stable.
Sorry for the long write up, but I'm a firm believer in providing information, when I'm asking a question, so that you, the respondent, don't have to ask the basic questions that I should have already provided
thanks for your assistance.
The coolant Temp guage goes to the center position fairly quickly and stays there, but every once in a while, I'll see the needle swing towards the 3/4 mark (halfway between center and Red)...then after a couple minutes, it will go back to center.
Now I've checked the coolant level and its fine, it also does not appear to have particulates or sludge.
The electric fan kicks on as it should. It is also running for a period of time after I shut the car off.
What I am thinking is either I have air in the system from the previous owner not having it properly filled/bled, AND/OR, I have a failing thermostat.
I called the Seattle Jag service center, but the conversation I had with the service advisor left me still with questions. Not that I question her knowledge, but it seems that "maybe" she didn't have a firm grasp on her technical skills.
I was told this is normal for Jags, to have the temp swings, ie the thermostat stays closed during normal temps, then when the coolant reaches a certain temp, the thermo opens up again/fan kicks on, temp needle goes back to center, thermo closes again, when temp rises, thermo opens again....rinse repeat.
I've owned many a car, and worked on them all
I've never heard of this as being "normal" behavior
My experience, is that the thermo will open once the engine temp reaches 185 degrees or so (depends on the thermo) and then it modulates how open/closed it is to keep the temp stable.
Sorry for the long write up, but I'm a firm believer in providing information, when I'm asking a question, so that you, the respondent, don't have to ask the basic questions that I should have already provided
thanks for your assistance.
Last edited by cryhavoc38; 08-23-2011 at 08:55 AM.
#2
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#5
Does the same thing regardless.
I'm convinced I have a sticking thermostat and will be removing it today to inspect and if necessary, install a new one from the dealer.
#6
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#7
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#8
Edited the main post.
The electric fan is working as it should.
Also, since I hear the fan running at different speeds at different times, the multiple temp sensors appear to be doing their job.
for instance, after a quick trip to the store, the fan will run at a lower speed. If she is hotter, or the ambient temps are warmer, I can hear the fan running at a much higher RPM, then it will reduce to a lower speed and then finally shut off.
I was reading some tech tips over at AutohausAZ and they state the following..
The thermostat is a spring-loaded valve that opens and closes based on the temperature of the coolant flowing through it. A high temperature reading followed by a drop to normal temperature (or a continuously low temperature) is a common first sign of a sticking thermostat. However, many other conditions may cause these symptoms, so you need to know how to eliminate each possibility.
Given that I feel the main water pump is working fine since I am not overheating, the radiator is clear of debris, the pressure cap is functioning properly, there are no leaks...after reading up and doing some searching on other Jag enthusiasts forums, A quick removal and inspection of the thermostat is in order. In the 06 S Type R, its a fairly easy proposition to remove the thermo.
Of course I could be misled in thinking this, but given the indications that I have...normal temp for the majority of the time, then the needle going to 3/4 guage for a minute or so, followed by a drop back to normal temp (driving down the freeway), its sure acting like a sticking thermostat. Not a stuck wide open situation which would show a low temp guage reading, but not being able to open enough part of the time.
Last edited by cryhavoc38; 08-23-2011 at 09:22 AM.
#9
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#12
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cryhavoc38 (08-23-2011)
#13
unbolted the housing from the thermostat housing.
Right away, I could see the lower portion of the thermostat was jammed inwards, causing more spring pressure to be exerted against the moving part of the thermostat.
as it turns out, this thermostat was assembled incorrectly. The smaller spring has a smaller diameter at one end and a larger diameter at the other.
The larger diameter side of the spring should sit in the brass colored lower assembly, with the smaller diameter side resting against the wax filled cylinder of the upper section.
The spring was reversed so that the larger diameter was causing movement interference against the upper portion.
Since i've removed it all, I'm just going to replace it anyways.
$52.08 for the replacement stat
$7.44 for the new O ring
A gallon of coolant
should be good as new when I get everything replaced/reassembled later this afternoon.
Right away, I could see the lower portion of the thermostat was jammed inwards, causing more spring pressure to be exerted against the moving part of the thermostat.
as it turns out, this thermostat was assembled incorrectly. The smaller spring has a smaller diameter at one end and a larger diameter at the other.
The larger diameter side of the spring should sit in the brass colored lower assembly, with the smaller diameter side resting against the wax filled cylinder of the upper section.
The spring was reversed so that the larger diameter was causing movement interference against the upper portion.
Since i've removed it all, I'm just going to replace it anyways.
$52.08 for the replacement stat
$7.44 for the new O ring
A gallon of coolant
should be good as new when I get everything replaced/reassembled later this afternoon.
Last edited by cryhavoc38; 08-23-2011 at 12:36 PM.
#16
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hunterworkz (08-27-2011)
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Just be aware with your old model 2001 the thermostat is a bit different and you need to remove some plastic cooling pieces that are known to disintegrate upon disassemble. So I would be ready to replace the plastic with new parts. Several good threads on this site about broken plastic cooling parts. Check it out BEFORE you start tearing into it!!
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Last edited by clubairth1; 08-27-2011 at 09:38 AM.
#20