Race update from sears point (scot is in trouble)
09-14-2006, 12:02 PM
#32
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Thread Starter
Im kind of on the same boat here, obviously.
However, i had the bum water pump on the Holbert car that slowely failed. finally, when it did, it wouldnt run 1 mile without seriously overheating.
maybe a partially connected impeller, but you would think that it would give way after one or two racing events. its very predictable.
now, i forgot one piece of information. i did use that chemical block test.
it did turn the blue liquid kind of yellow /green. i think that means exhaust gasses in the coolant. the instrument as a little bubble vacuum, where you sniff the air just above the coolant level in the expansion tank while its running warm. if thats the case, who knows where the leak is coming from . my rag tag leak down procedure failed to really show anything, and it doesnt use a drop of water around town!!
more of the same AHHHHHHHHH.
MK
However, i had the bum water pump on the Holbert car that slowely failed. finally, when it did, it wouldnt run 1 mile without seriously overheating.
maybe a partially connected impeller, but you would think that it would give way after one or two racing events. its very predictable.
now, i forgot one piece of information. i did use that chemical block test.
it did turn the blue liquid kind of yellow /green. i think that means exhaust gasses in the coolant. the instrument as a little bubble vacuum, where you sniff the air just above the coolant level in the expansion tank while its running warm. if thats the case, who knows where the leak is coming from . my rag tag leak down procedure failed to really show anything, and it doesnt use a drop of water around town!!
more of the same AHHHHHHHHH.
MK
Originally Posted by jon928se
Mark
If have read the posts correctly and hence the symptoms correctly - I'll summarise below
Leakdown shows all cylinders not leaking
No oil in the coolant
No coolant in the oil (A classic symptom of a cracked head on an early 32V engine - ask me how I know)
No obvious coolant leaks from duff coolant pipes or tstat bridge or housing or rad
It would probably cause a good non 928 mechanic at this stage to scratch his head.
However I reckon there are only two possibilities left
T stat aint working or
the water pump impeller has "fallen off"
Your last post would suggest the latter. Thats where i'ld go next.
Not related to Scotts car but FWIW I used the "Nanobot technology" ceramic block sealant about 4 years and 30k miles ago to succesfully seal a cracked head on my 88S4SE. no coolant use at all since (until the little hose between the block and heater valve blew!)
Cheers
If have read the posts correctly and hence the symptoms correctly - I'll summarise below
Leakdown shows all cylinders not leaking
No oil in the coolant
No coolant in the oil (A classic symptom of a cracked head on an early 32V engine - ask me how I know)
No obvious coolant leaks from duff coolant pipes or tstat bridge or housing or rad
It would probably cause a good non 928 mechanic at this stage to scratch his head.
However I reckon there are only two possibilities left
T stat aint working or
the water pump impeller has "fallen off"
Your last post would suggest the latter. Thats where i'ld go next.
Not related to Scotts car but FWIW I used the "Nanobot technology" ceramic block sealant about 4 years and 30k miles ago to succesfully seal a cracked head on my 88S4SE. no coolant use at all since (until the little hose between the block and heater valve blew!)
Cheers
09-14-2006, 12:04 PM
#33
Rennlist Member
Thread Starter
In thinking about it, you are probably right. probably need to put in a "fixed" themostat" to check flow from the pump. any other ways to check that. what about the flow to the water heater? that should be in a loop that is movinig, right? or is there no flow when the thermostate is closed. does it stall the water pump until warmup??
MK
MK
Originally Posted by littleball_s4
Not sure if I understood right your testing procedure, so forgive me if my question is very stupid:
Won't the thermostat prevent water from flowing trough the radiator until engine is hot?
Won't the thermostat prevent water from flowing trough the radiator until engine is hot?
09-14-2006, 12:19 PM
#34
Nordschleife Master
Originally Posted by mark kibort
what about the flow to the water heater? that should be in a loop that is movinig, right? or is there no flow when the thermostate is closed. does it stall the water pump until warmup??
the WP will recirculate the water through the block until warm then the thermostat will allow the water to the rad.
the heater valve lines can ba capped off without any problems as by closing the heater valve you are effectively doing this anyways.
there is another alternative to the WP/thermostat system but I cannot recall the name of the product, but you would cut the rad hose and remove a section and install a temp sensor in the thermostat housing, and remove the thermostat, you then also remove the impellor off the WP and install an electric pump in the rad hose to circulate the coolant. it is supposed to work really well
09-14-2006, 12:56 PM
#35
Race Car
Originally Posted by mark kibort
now, i forgot one piece of information. i did use that chemical block test.
it did turn the blue liquid kind of yellow /green. i think that means exhaust gasses in the coolant.
it did turn the blue liquid kind of yellow /green. i think that means exhaust gasses in the coolant.
09-14-2006, 01:01 PM
#36
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The thermostat when it opens allows coolant to flow back from the radiator into the thermostat housing BUT IT ALSO closes off the recirculation port in the back of the thermostat housing forcing all the coolant to flow into the radiator. As a test you can remove the thermostat BUT MUST block off the recirculation port , a rubber expandable "freeze plug" can be inserted to block that hole. At that point all the coolant should circulate all the time and the engine will not warm up quickly.
09-14-2006, 05:20 PM
#37
Rennlist Member
Thread Starter
Thanks Jim. I will try that. I was also thinking of just opening the lines at the back of the heads (that normally go to the heater core) if there is flow, wouldnt those lines have flow out and into them? if so, that maybe easier than taking an old thermostat and just fixing it open and reinstalling.
Good ideas.
mk
Good ideas.
mk
Originally Posted by Jim bailey - 928 International
The thermostat when it opens allows coolant to flow back from the radiator into the thermostat housing BUT IT ALSO closes off the recirculation port in the back of the thermostat housing forcing all the coolant to flow into the radiator. As a test you can remove the thermostat BUT MUST block off the recirculation port , a rubber expandable "freeze plug" can be inserted to block that hole. At that point all the coolant should circulate all the time and the engine will not warm up quickly.
09-14-2006, 05:35 PM
#38
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Reminds me of patients who, when a test came out badly, wanted to re-run the test. Unfortunately, you have your answer. Further testing won't change that, nor will it solve the head gasket/crack problem.
09-14-2006, 05:48 PM
#39
Rennlist Member
Thread Starter
I guess your right, but the color wasnt yellow, but it sure did change!!
so, the water pump is probably not the issue. Ill have to conduct that test on the holbert car, to see if maybe the test is too sensitive.
Maybe now its time to use the "Ceramic Block sealer" by "Nanotechnology". im a little suspicious of this kind of product, even though ive had great luck with head gasket leaks with barrs stop leak (different kind of leak now though)
otherwise, i guess the engine has to get yanked , yet again!!!!! poor scott!(poor me, 'cause, ill probably have to pull it with him again!)
MK
so, the water pump is probably not the issue. Ill have to conduct that test on the holbert car, to see if maybe the test is too sensitive.
Maybe now its time to use the "Ceramic Block sealer" by "Nanotechnology". im a little suspicious of this kind of product, even though ive had great luck with head gasket leaks with barrs stop leak (different kind of leak now though)
otherwise, i guess the engine has to get yanked , yet again!!!!! poor scott!(poor me, 'cause, ill probably have to pull it with him again!)
MK
Originally Posted by ErnestSw
Reminds me of patients who, when a test came out badly, wanted to re-run the test. Unfortunately, you have your answer. Further testing won't change that, nor will it solve the head gasket/crack problem.
09-14-2006, 08:02 PM
#40
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I've actually used the same stuff you used on my car back when I was (wrongly) convinced that it was overheating. I noticed that the color went from deep blue to a slightly lighter blue. I think it's a good idea to use it on several cars to get some idea of the range of sensitivity.
