Replacing thermostat and radiator, some questions.

[Silentbob343]

How many of you drained the coolant from the block when you replaced you radiator? It seems like a bitch to get a socket to that drain bolt on the block and it seems like the coolant would make a mess coming out from the side of the block.

Should there be any sealant around the thermostat housing? I am having a damn hard time getting the housing off and it looks like somebody uses a white sealant all around the edge. The only thing I saw in the FSM is a bolt and the gasket, nothing about using sealant.

[Silentbob343]

Does a 2 row radiator hold more fluid than the OEM 1 row? I just put in a whole bottle of 50/50 mix and I still haven't reached the top of the radiator.

[Silentbob343]

Well I just finished putting in the new rad and I noticed that the themostat that was in there was not a factory thermostat. The factory thermostat opening is much smaller than the one I took out, does this mean the thermostat that was in there was a low temp thermostat? It's odd becasue I thought that the dealership was the last place to look at my car when I was having overheating problems about 4 years ago.

I have a low temp thermostat, but didn't install it because I heard that low temp thermostats can be bad, i.e. car runs too rich becasue it's trying to get the car up to and keep the car at operating temp.

To the guy waiting on me to get measurments of the struts I promise you'll get them tomorrow after I get back from class. Sorry it is taking me so long.

[elscotto80]

I never used sealant when I did my thermostat. I would not worry about getting coolant all over the block, just rinse it off. As for filling it up, try to put in the least amount of coolant(enough so it will not freeze), then the rest water. Water cools much better than antifreeze does.

[Jho]

Draining the block wouldn't be a bad idea. Another option would be flushing the whole system, including the heater core. Go OEM on the t-stat. There shouldn't be any sealant around the t-stat housing. The o-ring that goes around the t-stat is the seal. The white **** you saw could've just been corosion. The size of the t-stat doesn't determine its temperature, its the spring. The temp of the t-stat should be stamped on the side of it somewhere. And just fill up your radiator till you see coolant.

[Silentbob343]

Yeah, I might flush the system today when I do my oil change or whait untill I get my tamp gauge. Where is a good place to hook up a temperature gauge to the B8 motor and a good line to tap into for the electrical connection, I'm guessing it just needs a 12V switched line.

For anybody who cares the 92 FSM list the ATX radiator as having a greater heat dissipation capacity than the MTX rad; 43,800 vs 38,800 kcal/h.

Here is on installation that I'm not crazy about:

http://www.scoobymods.com/forums/showthread.php?t=282

The ATX protégé uses a second thermo switch on the top of the radiator and on my radiator there is simply a brass plug since I have a MTX. Could this be a good location to mount the probe? After looking around there doesn't seem to be one location to install the temp probe, i.e. should I be trying to measure the coolant in the block, before the rad, or after the rad? Or is the location null as the coolant temp will be uniform throughout the system?

[Silentbob343]

I'm going to wait to flush the system, I figure I my end up loosing coolant during the gauge install so why not wait until then to flush the system.

2 questions;
First, what level should the antifreeze be in the overflow tank? The manual states to fill the radiator until it's full and then fill the overflow until the anti-freeze comes up to the lowest point on the dipstick, don't know what that plastic thing is called for the overflow tank. It then says to run the vehicle and fill the radiator again if needed yada, yada. I think it's still at the lowest mark, should I put some more anti-freeze in the overflow tank?

Second, where to install the temp gauge probe? Here is a picture of where the second thermoswitch would go on the ATX protégé.
New rad:

old rad:

Seems like a good spot to use as it's easy to get to and it is not being used on my car. Does it matter which plug/spot, i.e. left or right to put the temp probe in?

[ftjandra]

I think that it would make more sense to put the temp sensor before the t-stat. That way, you would get the actual temperature in the block and could tell right away if the t-stat stops working (i.e. stuck closed).

[Jho]

First, what level should the antifreeze be in the overflow tank? The manual states to fill the radiator until it's full and then fill the overflow until the anti-freeze comes up to the lowest point on the dipstick, don't know what that plastic thing is called for the overflow tank. It then says to run the vehicle and fill the radiator again if needed yada, yada. I think it's still at the lowest mark, should I put some more anti-freeze in the overflow tank?

The "indicator rod" for the expansion tank can be hard to read. There are also "full" and "low" marks on the side of the expansion tank with cooresponding lines. Thats what I go by. Just make sure the radiator and tank are full.

[Silentbob343]

I think that it would make more sense to put the temp sensor before the t-stat. That way, you would get the actual temperature in the block and could tell right away if the t-stat stops working (i.e. stuck closed).

Ok I can see that logic. Anybody have any recommendations for unused ports that would give access to coolant in the block?

[Jho]

The coolant plug that you were asking if you should remove to drain the block.