My GS350 (71 block/72 heads) is running hotter than I would like (non-air), around 205 driving around town with temps around 85-90. I have no idea what the current thermostat is, so I picked up a 180 at NAPA yesterday. Just bought the car last fall, so I don't know when it last had a coolant change. Since I'll need to drain some coolant to change the thermostat, I'm thinking I should just do a complete drain & replace. Haven't done this before, looking for any tips and suggestions anyone can offer. And what's the story behind a "power flush" at a shop? All they're doing is pressurizing to remove more coolant??? I've got air, so I can do that. Any comments are welcome...
David has the radiator ever been replaced? Here is what i do, I drain the coolant from the petcok on the radiator and then by the motor mounts there are twocoolant plugs (one on each side of the block) take these coolant plugs out and drain the block as well. some people who store there cars for the winter or do coolant changes put petcoks in these passages for ease of draining the coolant system. I would also go with the lowest themostat you can find probably 165 that way the cooling system does not have to fight uphill to get the temp lower. just my .02 , Later
Phil, I have a receipt for a new Modine radiator installed in 1999. I really don't want to mess with the block plugs. I don't have much of a "shop" to work in here. "Captain Mark" in Dallas says he goes without his thermostat during the summer. Any drawbacks to that? (I'm not planning to do it) Anyway, my plan is for the 180 thermostat, drain/flush/fill, and a new radiator cap.
I personally would not go without a thermostat but thats me. my understanding is that the thermostat slows down the fluid motion of the coolant and this also slows the time it spends in the radiator and adds for better cooling better cooling. some people use a body washer to slow down the coolant flow. you may also think about replacing the waterpump during this time unlss it has been done recent. they also have a recommended replacement time.
Last check is timing and adjusting points. maybe fuel adjustments running lean will cause your temps to go up also
Yeah, I was thinking I should pick up a vac gauge and adjust my air/fuel mix. I am, however, a complete novice when it comes to timing... o No:
David, If you don't know the last time the coolant was changed, I would go ahead and change it. Prestone sells a kit called a flush and fill kit. It includes a tee that is installed in the heater hose. You hook a garden hose to this tee and it will flush your engine completely. Then I would drain the motor using the radiator petcock, block drain plugs(they're easy), and disconnect the lower hose at the radiator. After that refill the system with no more than a 50/50 mix of antifreeze and distilled water(available at drug stores). I also like to add a bottle of Red Line water wetter and use the 160* thermostat. Actually the less antifreeze you use the cooler the engine will run.(water conducts heat better than anti freeze). You can actually run 100% water with the Red Line water wetter, it provides the corrosion protection but no freeze protection. I would also check your fan clutch and seal any space betwwen the fan shroud and the radiator so all the air is forced through the radiator. Hope that helps.
David - Regarding the thermostat, you DO need the restriction caused by the thermostat. If you want, some guys just gut the thermostat and put in the rest of it (looks like a big washer now) for the restriction. If the water flows thru the system too fast, it doesn't get the chance to effectively cool the engine!!:Smarty: You will probably find that this is what most circle track guys (chevy) do - IT WORKS!! Just don't forget to put in the thermostat if you drive it in cold weather!ou:
thermostat david: here is what i did . the water pump in my 72 gs crapped shortly after i purchased the car . since i had to remove the radiator to replace the pump , i thoroughly flushed it top to bottom the bottom to top. u should have seem the crap flying out of the rad . with the water pump off i was able to flush both sides of the block . it took a little while and all the muddy crap was finally washed out . by the way u do need a thermostat to allow the engine to operate more efficiently . u need some restriction to allow the fan and rad to perform their functions . i use a 180 thermostat . i also installed a 6 blade fan . i have used the preston flush kit and it works well on newer cars . however, i suggest that u do a complete flush job & not use the kit . good luck. gerry 72 gs 350
solved... Well, I found the problem. Someone must have been driving the GS year-round out in Oregon, 'cause I found a 195 thermostat in it. So, I flushed it with a Prestone flush kit, very clean coolant came out, no crap in it at all. Installed a 180, fresh coolant, and it doesn't go over 190, on a 95deg day. I have a 160, but I think I'll stick with the 180 for now. Now, if I could just solve the damn oil seepage from the new valve covers... :af: At the back of the driver side, and drips right on to the exhaust. ou:
David, You aren't using rubber valve cover gaskets, are you? I had the same problem as you are with the leaking until I switched to a cork gasket. Rob
No, I'm using cork gaskets from NAPA. But with these damn Poston aluminum valve covers, I can't get a socket down into the "groove" onto the allen head bolts to actually torque them to specs, so I'm going on feel, with a small allen wrench. With these covers, there's little to no space around the bolt holes for tools. I even had to over-drill all of the holes in order to get the bolts all started, they were so far off. I only used sealer between the gasket and cover...maybe should have put it on the head too... ou:
David, Its kinda weird you said about the valve cover holes being off. I bought a set of chrome valve covers for my '70 350 and the center holes were slightly off. So, I figured i got a set of bad valve covers but, when I put them on another set of Buick heads to test fit they fit perfectly. I'm wondering if Buick had two different hole patterns for there valve covers/cylinder heads? As far as your leak I would try a little sealant between the head and gasket where it is leaking at. Btw, that's a bummer you spent all that money for aluminum valve covers and they don't fit right. I hope you gave Poston's a piece of your mind. Rob
Actually, I got 'em from Year One, didn't know they sold Poston covers. I hear TA has real nice covers. Wish I would have shopped with them... I've had good and bad experiences with YO. Really don't plan on spending any more $$ there.
David G Phil mentioned using body washers as a thermostat, several companies make what they call restrictor plates to replace thermostats. Mine are Moroso and they come in three sizes, 1 inch hole, 3/4 and 5/8. He's right about no thermostat, you do need a restriction or the coolant goes through the radiator to fast and excess heat is returned to the motor. They cost about ten to twelve bucks but you could take some thin sheet metal in drill your own holes, just make sure it's not to thick or you'll break your housing. If your not into fabrication, send me your address and I'll mail you mine to try and see if it's what you need to take care of your problem. They weigh nothing so a stamp will do it both ways. Dave Berry
Thanks for the offer Dave B. For now, I'm good with the 180 thermostat installed. I'll have to keep that idea in mind though. I could have one made in our shop too. Good tip! :TU:
