JHZR2
Staff member
I have a 98 chevy s-10 with the 4.3L v6. UOAs have shown slightly elevated Na, K and about 0.1% glycol levels, but never higher regardless of mileage between changes.
I had the dealer change the intake manifold gaskets, and since auto rxed it (the levels came to be quite high after that, hopefully because of the autorx cleaning).
I am now driving it and waiting to get the miles up to send for a UOA to see how much glycol, Na and K is getting into the oil (I never notice any loss of coolant, head gasket checks out fine, etc) after the change, wth the amount hopefully being none.
Anyway, with the whole dex-cool/dex-clog issues with the 4.3L engines and so on, my research pointed me to a TSB that stated that a stant radiator cap be used for the system, rather than the standard GM cap. Apparently the stant cap seals better, keeps out air which canresult in dex-sludge formation and overall is a better choice.
However, the stant cap reccomended is a 16 psi cp, whereas the gm cap was a 15 psi cap.
Since doing this, I have noticed that the engine temperature creeps up after shutoff. Before, I could run the engine, turn it off, and only after a long highway drive with limited cooldown would the temperature needle creep past where it normally sits, and it would never creep that far. Since putting the new cap on, most any time when the engine is up to full temp for both the coolant and oil, I notice the temperature needle creep up after shutdown, if I start it up within 5-10 minutes. If I do this coming off the highway, with say a 30 second idle, it creeps up probably 20F! Even if just driving around slowly, it still creeps up some.
As soon as I start the engine, the temp goes back to normal, and NEVER fluctuates, regardless of ambient temp, load, etc. But it worries me that the temperature creeps up at all. It never boils over, I keep the coolant in good condition, changing it at twice the normal dex-cool interval at least, etc.
Am I damaging my cooling system badly by using this 16 psi cap, which allows higher constant operating pressure, and higher temperatures in the system after the engine turns off? I'd hate to ruin my radiator or risk blowing a hose or something else because of a silly radiator cap. I never had clogging or cooling issues while using the 15 psi cap, but I do have to worry, since I had the coolant to oil leak, and could be succeptible to clogging and other similar issues. Also, I'd have to guess that a higher pressure cooling system would make it more likely to devellop leaks into the oil, as compared to a lower pressure system, or even a system using something like evans waterless coolant, where I could run without any cooling system pressure at all!
Any advice? Should I follow the TSB and keep the stant cap, or should I go back to the GM cap?
Thanks,
JMH
I had the dealer change the intake manifold gaskets, and since auto rxed it (the levels came to be quite high after that, hopefully because of the autorx cleaning).
I am now driving it and waiting to get the miles up to send for a UOA to see how much glycol, Na and K is getting into the oil (I never notice any loss of coolant, head gasket checks out fine, etc) after the change, wth the amount hopefully being none.
Anyway, with the whole dex-cool/dex-clog issues with the 4.3L engines and so on, my research pointed me to a TSB that stated that a stant radiator cap be used for the system, rather than the standard GM cap. Apparently the stant cap seals better, keeps out air which canresult in dex-sludge formation and overall is a better choice.
However, the stant cap reccomended is a 16 psi cp, whereas the gm cap was a 15 psi cap.
Since doing this, I have noticed that the engine temperature creeps up after shutoff. Before, I could run the engine, turn it off, and only after a long highway drive with limited cooldown would the temperature needle creep past where it normally sits, and it would never creep that far. Since putting the new cap on, most any time when the engine is up to full temp for both the coolant and oil, I notice the temperature needle creep up after shutdown, if I start it up within 5-10 minutes. If I do this coming off the highway, with say a 30 second idle, it creeps up probably 20F! Even if just driving around slowly, it still creeps up some.
As soon as I start the engine, the temp goes back to normal, and NEVER fluctuates, regardless of ambient temp, load, etc. But it worries me that the temperature creeps up at all. It never boils over, I keep the coolant in good condition, changing it at twice the normal dex-cool interval at least, etc.
Am I damaging my cooling system badly by using this 16 psi cap, which allows higher constant operating pressure, and higher temperatures in the system after the engine turns off? I'd hate to ruin my radiator or risk blowing a hose or something else because of a silly radiator cap. I never had clogging or cooling issues while using the 15 psi cap, but I do have to worry, since I had the coolant to oil leak, and could be succeptible to clogging and other similar issues. Also, I'd have to guess that a higher pressure cooling system would make it more likely to devellop leaks into the oil, as compared to a lower pressure system, or even a system using something like evans waterless coolant, where I could run without any cooling system pressure at all!
Any advice? Should I follow the TSB and keep the stant cap, or should I go back to the GM cap?
Thanks,
JMH
