Coolant Temperature Rising on First Trip Out
01-19-2008, 11:06 PM
#46
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Hi Chris,
I've been driving the car around town and up hills and have not been able to get the temp up past mid-guage. I am surmizing that air may have been introduced into the cooling system when we used the heater for the first time in literally years. After a couple of cycles of draining and refilling and test runs, it seemed to settle down with time - i.e., I'm thinking it takes a couple/few cold start/warm up cycles with the heater on in order to self-burp. I believe this is one theory already posted here.
So, I haven't seen the return of the high temp guage. However, I'm still planning on doing one more complete drain (including block) to see if any more of those dark specks show up - probably Monday. If more than a few show up, I'm probably going to remove the radiator and take it to a shop to have them remove a tank and inspect/clean out the cores. Hope this helps....let me know if not.
I've been driving the car around town and up hills and have not been able to get the temp up past mid-guage. I am surmizing that air may have been introduced into the cooling system when we used the heater for the first time in literally years. After a couple of cycles of draining and refilling and test runs, it seemed to settle down with time - i.e., I'm thinking it takes a couple/few cold start/warm up cycles with the heater on in order to self-burp. I believe this is one theory already posted here.
So, I haven't seen the return of the high temp guage. However, I'm still planning on doing one more complete drain (including block) to see if any more of those dark specks show up - probably Monday. If more than a few show up, I'm probably going to remove the radiator and take it to a shop to have them remove a tank and inspect/clean out the cores. Hope this helps....let me know if not.
01-20-2008, 12:05 AM
#47
Drifting
Dwayne,
The Porsche Service Info by year Tech Spec Books are a great reference. These come on the Morehouse CD. Here's a page from the one for the 78' on the cooling system.
Note the comment at the bottom of the page about the bleeder lines. If your lines are not properly routed to allow air to bleed out into the reservoir, that would probably be the problem. They should have a continuous slope to prevent a water trap that would keep air from flowing back to the tank.
The Porsche Service Info by year Tech Spec Books are a great reference. These come on the Morehouse CD. Here's a page from the one for the 78' on the cooling system.
Note the comment at the bottom of the page about the bleeder lines. If your lines are not properly routed to allow air to bleed out into the reservoir, that would probably be the problem. They should have a continuous slope to prevent a water trap that would keep air from flowing back to the tank.
01-20-2008, 12:52 PM
#48
Three Wheelin'
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Dwayne,
The Porsche Service Info by year Tech Spec Books are a great reference. These come on the Morehouse CD. Here's a page from the one for the 78' on the cooling system.
Note the comment at the bottom of the page about the bleeder lines. If your lines are not properly routed to allow air to bleed out into the reservoir, that would probably be the problem. They should have a continuous slope to prevent a water trap that would keep air from flowing back to the tank.
The Porsche Service Info by year Tech Spec Books are a great reference. These come on the Morehouse CD. Here's a page from the one for the 78' on the cooling system.
Note the comment at the bottom of the page about the bleeder lines. If your lines are not properly routed to allow air to bleed out into the reservoir, that would probably be the problem. They should have a continuous slope to prevent a water trap that would keep air from flowing back to the tank.
I have the Morehouse CD package but never considered looking at other year service info files - only the '84. So I looked at the '78 file this morning - WOW! A lot more information on all systems than in the '84. Great diagrams and descriptions of where everything is and how it's supposed to work. This was one big piece of information that was missing for me and you just pointed me in the right direction.
THANKS!Thinking about it, this makes sense....why repeat the same information for each model year - only the deltas but the first year file would have the most complete information. AHHAAAA! I GET IT!! Now I'm going to read through all of them.
I believe the bleeder hose is routed correctly but I'll check it out anyway. THANKS for the tips!!
01-20-2008, 01:15 PM
#49
Rennlist Member
Dwayne,
Check-out the wiring diagrams for the 83. They are infinitely better than those for the 84, and most are the same circuits.
Also, check-out the electrical training materials, I think three files.
One appears to be an update that details some differences in charging system, alarms, tailgate release etc, between 84 and earlier years.
Check-out the wiring diagrams for the 83. They are infinitely better than those for the 84, and most are the same circuits.
Also, check-out the electrical training materials, I think three files.
One appears to be an update that details some differences in charging system, alarms, tailgate release etc, between 84 and earlier years.
01-21-2008, 11:12 PM
#51
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... However, I'm still planning on doing one more complete drain (including block) to see if any more of those dark specks show up - probably Monday. If more than a few show up, I'm probably going to remove the radiator and take it to a shop to have them remove a tank and inspect/clean out the cores...
This is what came out the first time I drained it a couple of weeks ago:
So what came out this time was a little more than I wanted so it looks like I'll pull the radiator and have the tank(s) removed and inspect the core at a radiator shop. I'm hoping it will reveal the specks are coming from the radiator. Since the number of particles is not too high, I'm not planning on jumping on this right away - probably spring or right before summer. Just wanted to close the loop for those watching. Oh, still no return of the high temps, BTW.
06-10-2009, 09:31 AM
#52
Team Owner
Dwayne there might be another thing to consider, replacing the oil thermostat and its springs, this part is just above the oil sender mounting collar. From your postings it sounds like things may be OK but this could be a problem as once the oil heats up then the thermo wont allow enough oil into the cooler to cool things down just a FYI
06-10-2009, 06:29 PM
#53
Rennlist Member
The heads measured between 205F and 210F. The radiator core at the cool/return end (driver's side of the car) had some interesting readings. Near the top, next to the side tank, the temp was between 110F and 115F. As I moved down the radiator core with the IR, the core/cooling vane temperature steadily drops - midway down the radiator core temp is about 95F and at the bottom it's about 80F. I couldn't get a good position to take readings on the other end of the radiator (at the inlet/hot end).
06-10-2009, 10:40 PM
#54
Three Wheelin'
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Dwayne there might be another thing to consider, replacing the oil thermostat and its springs, this part is just above the oil sender mounting collar. From your postings it sounds like things may be OK but this could be a problem as once the oil heats up then the thermo wont allow enough oil into the cooler to cool things down just a FYI
06-10-2009, 10:47 PM
#55
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IMHO this indicates the lower core tubes are plugged. It should be nearly the same temp top to bottom(checking the core tubes along a vertical line top to bottom). I had the same issue, same sort of IR measurements. I replaced the radiator and took the old one apart out of curiosity -- lower tubes all plugged with what looked like stop-leak.
06-11-2009, 01:59 AM
#56
Rennlist Member
I didn't have the exact same readings, but it was the same pattern. All may be well until you ask a lot of it. You could run for a long time with a very small buffer of extra cooling capacity, then one day the temp, humidity and driving conditions can all work against you at the same time and you have a problem again. It's definitely worth double-checking based on the initial observations you reported.
The actual measurements are not that important -- too many things can influence the number you see displayed, from the quality and/or D:S of the unit to the emissivity of the surface you are measuring(check the D:S -- you may not be measuring what you think you are) to the emissivity calibration of the thermometer. What matters most is the differences between points that are measured. I can check when I get home tomorrow but I think the top-to-bottom delta on mine is usually around 5°F or less.
The actual measurements are not that important -- too many things can influence the number you see displayed, from the quality and/or D:S of the unit to the emissivity of the surface you are measuring(check the D:S -- you may not be measuring what you think you are) to the emissivity calibration of the thermometer. What matters most is the differences between points that are measured. I can check when I get home tomorrow but I think the top-to-bottom delta on mine is usually around 5°F or less.
06-11-2009, 09:54 PM
#57
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Sounds good, Dave. I'll be interested in what you find. Meanwhile, I don't expect to have access to Rennlist while I'm making my drive across the country tomorrow but I should be able to check in Sunday/Monday when I arrive home in CA. THANKS!
09-07-2010, 04:56 AM
#60
Rennlist Member
Resurrecting an old thread here, but I learned a lot from it...
Its been my understanding that head temperature is more a result of oil temperature, than coolant temperature.
??
