[tamathumper]

My car has been running hotter this year, at the 9:00 position, and now even getting up to the white line at 10:00!



I searched and read all of the threads I could find regarding high temps, and the different tests and combinations of failure of the fan switch, thermostat, fan relay, and even the fan fuses and AC pressure switch.



I've bled the car three times since installing the supercharger per Clark's Garage (turning the heater on full), and I'm reasonably certain it's free of air, although I haven't had the front of the car elevated while doing it, if that matters?



So today, I started the car and let it idle a while, and pressed the AC switch and ensured the fans came on, and turned off when I disengaged it. A/OK.



It idled at 9:00 quite a while with temps of the upper radiator hose (at the engine) of 185-195 and for the lower hose 110-170. The fans came on low and turned off from time to time. The temperature gauge was steady.



Then, for no apparent reason, it was off to the races, so to speak. The temperature gauge went to 9:30 and stayed there, both fans came on low, and the temperatures went to 185-195 and 108-113 for the upper and lower hoses respectively. It stayed in this exact state for 5 minutes with the fans running on low and the temperatures (and temperature gauge) steady.



So, the fans seem to be working, and the lower hose gets very hot (sometimes) but not always (the water pump was new two years ago), but I don't see these exact symptoms in previous threads?



Is it possible the water pump is slipping sometimes and not others? Or the thermostat is failing closed intermittently?

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[tamathumper]

Pete says, in another post:

One of the keys to a failed WP is engine overheating without fans coming on. The WP isn't pushing hot water past the Thermoswitch

... so since my fans are coming on, I'm thinking my water pump is OK?

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[Cloud9...68]

The fact the the rise in your temp gauge reading seems to correlate to a drop in temperature of your lower hose makes it sound like you have a sticking thermostat. When was the last time you had yours replaced?

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[tamathumper]

Thanks for your reply, Cloud. Probably never! I had the perfect opportunity when I did the supercharger, but I didn't read that far ahead in the instructions and missed my chance. I had the job started and was too excited to put everything on hold.



I thought maybe the thermostat was working because the temps on the lower hose were dropping, is that not correct? I don't have a good sense of how the coolant flows under different circumstances on this car, the thermostat seems to be in a funny place.

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[Cloud9...68]

I believe the fat lower lose is the return hose after the coolant makes a lap through the system, the last leg of which is through the radiator, if the thermostat is open. If the thermostat is closed, water never flows through the radiator, and the lower hose will remain cold. At least that's my understanding of it, which is probably incomplete at best. But I do remember when I had a bad thermostat, the bottom radiator hose never got hot, and the new thermostat fixed that.



If you're going to remove the thermostat, do yourself a favor and buy a pair of long-handle needle nose pliers, with the tip at a 45 degree angle. I also filed the tips of my pliers down so they would fit into the holes of the thermostat's retaining ring. Having a tool like this makes the job, which I've heard many people complain is a real pain, very easy. Still messy, but easy.

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[tamathumper]

So, at least the hose got hot at one point, but then it cooled down, and I just need to figure out if it was because the thermostat was closed (and water wasn't flowing), or it cooled down because the thermostat was open (and water was flowing through the radiator with both fans running)? Argh!

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[flash]

sounds like either the thermostat is sticking, or the watermpump impeller is spinning on the shaft



either way, you're probably taking it apart to find out.



by the way, the thermoswitch has nothing to do with the watermpump. it doesn't block the flow at all, and merely reads temp and sends power to the fans accordingly

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[tamathumper]

Poop, well then I guess it's time to tear into it. Thanks for the advice.



I suppose I should replace that lower hose while I'm in there, too. Any other WYIT recommendations?



I just did the Clark's Garage test of the fan relay using a jumper wire, and it tested OK in all positions.



Is there at least an "unmessy" way to drain the coolant? When I did it to install the supercharger, it was seriously messy,...!

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[flash]

yes - i can drain the radiator without spilling more than a couple of drops (not that i haven't screwed up plenty of times).



when you get the car in the air, tilt the car slightly toward the driver side. 1/2" - 1" will do it.



drop the splitter or front apron, depending on which you have (yes, it must come down)



remove the brackets holding down the radiator



remove the airbox, and the radiator heat shield.



now you have access to the bottom of the radiator, and can stuff a rag between the radiator and the support tray to prevent fluid from running along the tray to the passenger side.



crack the overflow cap loose, as well as the bleed screw.



use a sluice gate under the drain plug, like i mentioned in the installation instructions.



hold the drain pan under the plug, up close to it, until it starts to flow, then lower it under the flow pattern, anticipating the decrease in flow as it drains.



when it stops draining, put the drain plug back in, but leave it loose for now, in case you need to remove it again.



move your drain pan back to the passenger side.



loosen the clamp on the lower hose.



gently pry the hose loose and off the radiator, but only enough to let the fluid out.



when it stops draining, stuff a rag in the hose.



wait for 15 minutes.



remove rag and remove hose.



begin the work on the pump/thermostat.



don't forget to tighten down the drain plug when you're done

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[tamathumper]

Holy cow. I think I spilled all BUT two drops.



Do I tilt the radiator? Is that why I have to remove the upper holders?

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[flash]

you can't lift the radiator to get the rag under there without it. also, you really can't get to the plug, or the hose very well with it in place. basically it needs to float.



it's all about how clean you want this to be. you can skip all of that and just make a mess. but to do it clean, you need to do it all.

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[Lear35A]

Flash is correct. It is possible. I've had to drain the radiator many times and get better with each attempt. Every time I have said I need to put a little extension from the radiator hole to a plug. If you can get the discharge past the lip of the lower radiator pan, it would be a piece of cake. Sad to say I've never done it. I kept thinking "gee, this has got to be the last time I have to do this." WRONG

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[flash]

sluice gate

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[tamathumper]

I little radiator petcock would be the ticket! Maybe next time, surely I won't have to do this again. <img src="/forum/images/smilies/968/biggrin.png" class="smilie" alt="" />

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[flash]

lol - that only gets part of it though. you would still have to deal with the lower hose and the mess that makes. not sure i want a petcock in a plastic tank though.

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[Lear35A]

You can pull the radiator with the lower hose in place. Disconnect from the water pump and leave it connected at the bottom. Solve the mess from the drain plug, and you've got it.

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[flash]

hmmm - all my thermostats are drilled, so that doesn't work for me

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[tamathumper]

Drilled? Is that something you do to them after you purchase them, or do you purchase them that way?

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[Lear35A]

I drilled my thermostat. As long as you drain the radiator first through the bottom plug there is no coolant level above the water pump. It works just fine to leave the lower hose on.

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[tamathumper]

Found reference to it on the forum. The recommendation seems to be one 1/8" hole drilled in the thermostat, but flash posted a picture showing what looks like six holes drilled in the thermostat,... is there one preferred over the other?

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