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Discussion Starter · #21 ·
Interesting. The thermostat was replaced last year when the head gasket was replaced so that is not the problem here. I talked to the mechanic who did the work on my car and he said they use a special coolant tool to draw 25 inches of vacuum to check for leaks and then draw in the coolant to prevent any air in the system. Using a tool like this would make my clogged purge tube a moot point - if they really work. Has anyone had any experience with one of these tools? I would gladly invest in one if they were effective at getting all the air out.

Tom
 

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To throw in another data point mine will hit 231, however, it will only do this in second gear on a long climb up to Lake Tahoe which I'm sure being in Sparks you're familiar with. Are you getting these numbers on flat ground or while going up a long steep incline that forces you into second gear?
 

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This was on a vehicle that Scott did the Radiator replacement on and fixed a coolant leak. It has no history of head gasket issues and really has no issues or codes since he went through it all beside the battery is starting to act up in the heat.
 

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Discussion Starter · #24 ·
I live near Prater Wy and El Rancho so the short jaunt from there to the Vista offramp and back home via 80 Fwy is enough to hit 231F in 5th gear when it is 100+F out. Today was a bit cooler out so it hovered around 224F mostly but still climbed to 231 a few times. I find it strange that the dash temp gauge considers 231F as "normal" - still 6 to 7 bars like there is no problem at all. A/C needs topping off but other than that everything else works fine with over 220K miles on car.
 

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I have never looked at the OBDIIC&C for coolant temp.. I just use the factory gauge that never goes past 1/2 way.

Thanks for posting the coolant "burping" video, here is a link to an EGR cleaning flexible drill bit that may work to clean the passage:

SUR&R® EGR9 - EGR Drill Bit - TRUCKiD.com
 

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3/16" dia. drill. I don't think that would work but a good find though.
 

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Discussion Starter · #27 ·
It seems long enough but just not flexible enough to make the two 45 degree bends. I made a 176 mile trip to a house my son bought in Winnemucca and the red LED indicating overtemp on the OBDIIC&C was on constantly never went over 231F. Also, the dash temp gauge never went out of the "normal" 6 to 7 bars. Strange.
 

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I have one other idea I picked up from Scott today. Maybe your coolant temp sensor is bad. You could check this, after a fashion, by using an IR Thermometer. You can buy them for as little as $15 at various internet sites. If you want to, check it with boiling water, corrected for your altitude. (About 203.5F in Sparks.)
 

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Discussion Starter · #29 ·
I have considered that but it doesn't explain the discrepancy between the dash temp gauge reading "normal" (6 to 7 bars) but the OBDIIC&C data reading over 217F most of the time. I am assuming they both get their data from the same sensor - right? The only explanation I can see is if the OBDIIC&C reader is giving me erroneous data for some reason. I might add that once in a great while the OBCIIC&C will instantly drop to a fixed reading of 0032 for a few seconds and then jump to its readings in the 200F range. I suppose this could indicate an abnormality in the OBDII reader - bad solder joint etc. Just too many things that do not make sense but keep in mind that I never experience the obvious observations of coolant overflow or anything of that sort. All external indications are that things are normal which agrees with the dash gauge readings of 6 to 7 bars. Hard to understand which indications to trust.

TA
 

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No. The OBDIIC&C gauge is correct. The temp gauge was purposely designed by Honda to be "numb" in the center and carry a wide range of temperatures without moving.

I can't imagine you driving it this hot. Mine would be parked until I figure it out. I don't like pulling heads.

Sam
 
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Discussion Starter · #31 ·
I wish I had the luxury of parking it but I am single and have no other means of transportation. I wish I did. So what you are saying is that the in dash temp gauge is totally worthless and useless. You can be in a overheating condition but will not know it because the gauge is reading "normal". For a car that is technically designed so perfectly in every other respect, this sounds like an absurd and insane decision on the part of the engineers. So, if the gauge ever reads above "normal" then it is telling you that you have just destroyed your engine. I wonder how hot it has to get before the gauge ever decides to move again? 240F, 250F, when the oil starts boiling? I am doing my best to figure out the problem but every path leads to a dead end. I am at my wits end.
 

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I wish I had the luxury of parking it but I am single and have no other means of transportation. I wish I did. So what you are saying is that the in dash temp gauge is totally worthless and useless. You can be in a overheating condition but will not know it because the gauge is reading "normal". For a car that is technically designed so perfectly in every other respect, this sounds like an absurd and insane decision on the part of the engineers. So, if the gauge ever reads above "normal" then it is telling you that you have just destroyed your engine. I wonder how hot it has to get before the gauge ever decides to move again? 240F, 250F, when the oil starts boiling? I am doing my best to figure out the problem but every path leads to a dead end. I am at my wits end.
Correct. The dash gauge is nearly worthless. Experienced Insight owners have known it a long time. I don't know why Honda let such a poor gauge sneak into the car, the poor accuracy is well know.

From my observations, the OBDII C&C is pretty darn close. I've used it a long time and I trust the temp reading. Yes, it does have the bug of occasionally reading 0032, in some versions, but otherwise it is accurate.

Please take my suggestion back in #28 and do an independent measurement. With an IR thermometer, you can measure the head temperature, and the temp of the coolant hose as it exits the engine. I think it is the upper hose, but not sure - check both. I'm not going to contribute again until you provide some genuine feedback;)
 

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Discussion Starter · #33 ·
I will look into picking up an IR thermometer then and post when I have results.
 

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I'd be very interested to know the DC-DC temperature (DTE) at the time the coolant temp exceeds 125F. Thanks
 

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I wish I had the luxury of parking it but I am single and have no other means of transportation. I wish I did. So what you are saying is that the in dash temp gauge is totally worthless and useless. You can be in a overheating condition but will not know it because the gauge is reading "normal". For a car that is technically designed so perfectly in every other respect, this sounds like an absurd and insane decision on the part of the engineers. So, if the gauge ever reads above "normal" then it is telling you that you have just destroyed your engine. I wonder how hot it has to get before the gauge ever decides to move again? 240F, 250F, when the oil starts boiling? I am doing my best to figure out the problem but every path leads to a dead end. I am at my wits end.
It's not just Honda. It's common with brands that actually have temp gauges. Mazda comes to mind. Miatas have been this way since day one. It's done to keep owners from worrying about it when the temp gauge starts going up. It mostly works, but when it moves out of the dead zone it's time to do something.

Sam
 

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It's not just Honda. It's common with brands that actually have temp gauges. Mazda comes to mind. Miatas have been this way since day one. It's done to keep owners from worrying about it when the temp gauge starts going up. It mostly works, but when it moves out of the dead zone it's time to do something.

Sam
between a degree and shop time I've seen a few cars and it's actually the vast majority of cars that are like that... for most types of gauges too. Ford's run the oil pressure gauge in everything to an on/off switch since the 80s: if you have more than 4psi the gauge reads dead center. the reason's the same for all of them: They don't want to deal with customers saying "OMG the gauge twitched you need to warranty me a new engine". Having dealt with more than a few customers: it's true. The vast majority of owners would have their minds blown if they actually saw how much the engine varied it's conditions. My older toyotas were in the middle of the gauge +/-1/8" from about 160-230. Here's how to read the gauge on 99% of cars: if it's below the center, don't beat on it it's still really cold. If it's above center pull over immediately, it's stupid hot.
 

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Discussion Starter · #37 ·
Thanks for that - so it appears most gauges are no better than the old "idiot lights". Interesting.
 

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Discussion Starter · #38 ·
So I went to Harbor Freight and bought an IR thermometer to record head and radiator hose temps, and wouldn't you know it - its only 93 out today and ECT is reading 213F or less with the temp LED mostly staying off. It occasionally would hit 217F but would come right down once the car was at idle. This was all on surface streets so I will the freeway later to see if it will climb higher.
 

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Good data, but the coolant temps are too high. A normal Insight cooling system temperature is under 200F in most occasions, and it does not spike like that. I just don't know but it seems to me the best thing to do is to route out the purge tube like Scott suggested. When he talked about using welding wire I assume that he was talking about MIG wire. I can mail you a piece if you don't have a source. It sounded to me like his technique was easy enough to do with an ordinary electric drill. I've lived in trailer parks and electricity is always available. I think you are going to have to work harder at this.

Assuming that you can purge the system, it will probably solve the problem, but if it doesn't then you have to look at options like a partially plugged or leaking radiator.

Take it in steps with the purge tube first:)

JMHO
 

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Discussion Starter · #40 ·
Thanks again JMHO for your input. You are again verifying my suspicion that there is not something right with the cooling system and it goes beyond simply burping the system correctly. The shop that did the head gasket replacement specializes in hybrids and they did a very credible job. It was just July a year ago that they finished the head gasket replacement and they followed up with work to prevent other cooling problems in the future - installed brand new radiator, new hoses, new thermostat, and flushed the system. I didn't install the OBDII reader until a few months ago, if I would have had it in last year this I would have known about the high temp readings sooner and started diagnosing it then. I feel confident that there is not a cooling component failure common to most cooling problems. It is something more esoteric and I keep coming back to the carbon blocked purge tube. After reflecting on this for weeks now I have come to the conclusion that not only is the purge tube blocked but probably a good portion of the cooling cavity (I can't remember the actual term Honda uses) where the purge tube and bleed valve attaches to is also blocked by carbon. God only knows how long the previous owner ran the car with the blown head gasket before I bought it and I drove it myself for quite awhile before I was convinced it was a blown HG. Exhaust gases (and carbon) have been circulating through the cooling system for some time and I believe it has built up and is clogging the normal coolant circulation. I have worked on cars for years and understand cooling systems pretty well - this is the only explanation that makes sense to me. There are just too many brand new parts in the cooling system. If I am right, then the only way to fix it correctly is to replace that part with the purge tube and bleeder valve. I can clean the purge tube with the MIG wire but will still have the problem if the cavity below the purge tube is still built up with carbon. The shop I deal with is taking appointments 3 weeks in advance at this time so no matter what I am forced to wait. I have a van in storage that needs some work to get running - I will have to resurrect it to have a vehicle to drive while the Insight is being worked on again. If I am missing something - I am all ears.
 
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