MasterGuns Posted July 16, 2009 #1 Posted July 16, 2009 Can a defective radiator cap cause coolant to bubble (for my lack of a better description) back into the overflow bottle? I believe coolant returning to the overflow is normal, I've just never heard it doing so. This only occurs when the motor is really hot. I've had several lst Editions and I've never had one do this even when touring in and through Death Valley (Furnace Creek) in 110+ weather. My temp guage was only a little past half way when I stopped today (108 here in Dallas) and killed the engine and within a few seconds this gurglling/bubbling sounds starts and today I even had some coolant run out the overflow line and puddle underneath the rear of the motor. Weird. I picked up a new radiator cap and hope this solves this issue. The radiator is clean, no clogged cooling fins, good thermostat, water pump in good condition and Engine Ice as coolant. Any advise would be highly appreciated.
Venturous Randy Posted July 16, 2009 #2 Posted July 16, 2009 Pressure causes the boiling point to increase. If you do not have adaquate contained pressure, you may be more susceptible to boil. I would replace the cap and see what it does, or at least check the tabs and seal and make sure they are ok. RandyA
Guest HdHtr Posted July 16, 2009 #3 Posted July 16, 2009 (edited) Hey Guns. By all means replace your radiator cap. They are cheap and only takes a few seconds to do. Also, if you've changed the coolant recently, check your petcock and make sure it is in the right position. Edited July 16, 2009 by HdHtr
massey130 Posted July 16, 2009 #4 Posted July 16, 2009 the caps are designed to lift & allow boiling coolant to escape into the overflow reservoir. when the engine is cool enough, you add the coolant back to the radiator. My 2ndGen has a fan that i allow to run rather than turning the key to off on hot days. it hasn't boiled over, but south Louisiana heat makes for a hot motor. automobiles do the same thing.
MasterGuns Posted July 16, 2009 Author #5 Posted July 16, 2009 Alright fellow members, I have already purchased a very expensive replacement rad cap for 6.58 from Autozone. When I have the time (this weekend), I am going to drain and recover what I can of that expenisive Engine Ice I have in the cooling system now. Then I am going to add some sort of radiator flush product. Hopefully I can find a flush designed for aluminum engines. I am going to flush using whatever a couple times. Replace the coolant and the $6.58 radiator cap. Then take it out on the freeway to check her out. Will advise the results, if any, afterwards. I am doing this because I know a lot of 1st Gen owners have the same high operating engine temp as I have especially when operating is hot areas. North Texas is a "hot" area, and in more ways than just the temp. Anyway, one last question: Has anyone ever used a "chemical" to flush their cooling system and if so, what? Standing by!
93 venture Posted July 16, 2009 #6 Posted July 16, 2009 You might want to make the mix more like 50/60 or 50/70, more antifrezze will bring up the boiling point. dont use pure antifrezze it will make your waterpump seals leak.
MasterGuns Posted July 16, 2009 Author #7 Posted July 16, 2009 comes pre-mixed. You add it straight from the container. Besides this "boiling over" after killing the engine also occurred with regular antifreeze of varing mixutures. This is something wrong; defective cap, stuck thermostat, inside of radiator in need of descaling, something. Eventually, I will be to the bottom of it. Thanks You might want to make the mix more like 50/60 or 50/70, more antifrezze will bring up the boiling point. dont use pure antifrezze it will make your waterpump seals leak.
Russ Posted July 17, 2009 #8 Posted July 17, 2009 my 1st gen is doing this too, however it overheats first. strange thing is it's seemingly random. once after 150 mile shakedown run, once after a 75 mile shakedown run, once after 20 miles. let it sit and idle for two hours and nothing. Squidley recommended I replace the radiator cap. I looked into the OEM replacement for it. I wasn't aware that there's one I can pick up at autozone... would you possibly have info on which cap to get? and has anyone here used a non-OEM cap on their 1st gen?
rhncue Posted July 17, 2009 #9 Posted July 17, 2009 my 1st gen is doing this too, however it overheats first. strange thing is it's seemingly random. once after 150 mile shakedown run, once after a 75 mile shakedown run, once after 20 miles. let it sit and idle for two hours and nothing. Squidley recommended I replace the radiator cap. I looked into the OEM replacement for it. I wasn't aware that there's one I can pick up at autozone... would you possibly have info on which cap to get? and has anyone here used a non-OEM cap on their 1st gen? It's a Stant #13758 or you can cross reference to another brand. "has anyone here used a non-OEM cap on their 1st gen?" The question should be "Has anyone ever used a OEM radiator cap?" Dick
Russ Posted July 17, 2009 #10 Posted July 17, 2009 It's a Stant #13758 or you can cross reference to another brand. "has anyone here used a non-OEM cap on their 1st gen?" The question should be "Has anyone ever used a OEM radiator cap?" Dick Just looked up the Stant #13758... that's the Thermostat. http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Thermostat---OE-Replacement-Stant_5653266-P_133_R|GRPCOOLAMS____
93 venture Posted July 17, 2009 #11 Posted July 17, 2009 I could be wrong but i think a cap from a Geo Metro was the same.
MasterGuns Posted July 17, 2009 Author #12 Posted July 17, 2009 That's right; the rad cap from a 93 Geo Metro is the same as the OEM cap from Yamaha. Part #156 from NAPA. Or at least that is what I've read on this site. I bought one yesterday (about 8 bucks), checked it out real close and then ordered the stock Yamaha rad cap as it appeared to be a little different. I'd rather be absolutely positive I have the right cap on especially in these seemingly constant 100+ degree days here in North Texas. Just my 2 cents.
chocking Posted July 22, 2009 #13 Posted July 22, 2009 my 84 occasionally does the same thing.. Never loses any rad fluid and only when hot city driving, but temp is never much over 1/2. If you figure out the reason, be sure to let us know...Maybe I need to look into a new cap as well.
MasterGuns Posted July 22, 2009 Author #14 Posted July 22, 2009 Replaced the rad cap with a new one and bingo, all the boiling over, gurgling and carrying on after getting it really hot and then killing the motor has STOPPED. If anyone's bike is doing this, replace your rad cap.
painterman67 Posted July 22, 2009 #15 Posted July 22, 2009 Hey Guns. By all means replace your radiator cap. They are cheap and only takes a few seconds to do. Also, if you've changed the coolant recently, check your petcock and make sure it is in the right position. thanks for the pic I've been wandering if I put it back on wright. David
Steve S Posted July 23, 2009 #16 Posted July 23, 2009 Stupid question here, but was your cooling fan working properly? The coolant stops circulating, and gets the hottest, when you first shut off your engine, hence the "boil over". That is when your fan should run, if only for a minute.
MasterGuns Posted July 23, 2009 Author #17 Posted July 23, 2009 Stupid question here, but was your cooling fan working properly? The coolant stops circulating, and gets the hottest, when you first shut off your engine, hence the "boil over". That is when your fan should run, if only for a minute. That was the first thing I checked and it (the fan) works fine. Ah, 1st Ed fans do not continue to operate once the engine is shut down. I've owned 1st Gens since 1986 and this is the first one that did this boiling over thing, and perhaps the weather aroung here (107+) most likely had a lot to do with this but I have solved the issue. No more boil over.
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