2F temps (1 Viewer)

[73lndcrsr]

I just put a 2F in my 73. I had the radiator cleaned and used new hoses and thermostat (with both gaskets). I am running an older water pump w/o fan clutch. It does not want to get above 130 deg while running. If I pull a long steady climb, the temp guage creeps up to 180, but immediatly starts droping back when I start it.

My first thought is the thermostat. Is there something else I should check?

 

[Archengine]

Sounds way too low, kinda like what happened to me. Your thermostat is sticking open or your missing the top gasket over the thermostat. I forgot the gasket on mine, and I won't even get to 130 right now. I'm changing it this weekend, too cold outside.

 

[folsom50]

I'm dealing with the same sh*t 73, I just rebuilt the 2f in my '78 and I can't get the needle on the gauge to get into the "normal" range. If I block off half of the radiator with cardboard it gets too hot. I can't picture anyone having problems cooling a stock sbc with this cooling system! Of course, it is 7 degs. right now.

 

[73lndcrsr]

It was a balmy 35 for me. I will have to check the t-stat and gaskets. I know I put both in there and I don't think you could install it backwards.

 

[folsom50]

I'm going to do the same when I get back from vacation, I can't even get the rings to seat on my rebuild.

 

[Cruiserdrew]

There are only 2 things this could be-either the thermostat is stuck open, or the upper gasket is missing or installed incorrectly. If the thermostat is new, then it's even more likely to be the upper gasket. Either way, the thermostat housing needs to be opened up for diagnosis.

 

[mwalls54]

How important is the upper gasket? i am having the same problems. my temp goes up and down and is never constant.

 

[Poser]

Seals the top of the stat to the housing, making it so that ALL coolant that flows through the stat, does so. Otherwise, a situation like what you are describing could result.

Good luck!

-Steve

 

[mwalls54]

ok next question what does the top gasket look like? i put the new tstat in because it didn't have one to start with i had to make the housing gasket out of regular gasket material. should i use the same material on the top.

 

[IDave]

Its a ring-o-rubber about 2 inches or so in diameter.

The lack of it is an excellent indicator of the efficiency of the FJ40 radiator 8).

I guess you could make one, but it would have to fit just right. Probably worth the trouble to head down to the NAPA store and purchase one.

 

[folsom50]

Its a ring-o-rubber about 2 inches or so in diameter.

So that's what one of my "left-over" things is for out of my rebuild kit, I couldn't figure out where that 2" o-ring could possibly go on a 2f.

 

[mwalls54]

what is the thickness of it. thanks guys for the help

 

[Slowerthanu]

funny, I have never run that gasket, come winter I stick a piece of cardboard in front of the radiator.

 

[IDave]

I tried the cardboard trick (until I found out about the missing gasket). Cardboard worked well until about 15 miles down the road, when things got too hot and I had steam and antifreeze coming out all over the highway.

 

[Poser]

[quote author=mwalls54 link=board=1;threadid=8460;start=msg71984#msg71984 date=1070678640]
what is the thickness of it. thanks guys for the help
[/quote]

Little bit more than 1/8 of an inch.

 

[Slowerthanu]

[quote author=IDave link=board=1;threadid=8460;start=msg71999#msg71999 date=1070679618]
I tried the cardboard trick (until I found out about the missing gasket). Cardboard worked well until about 15 miles down the road, when things got too hot and I had steam and antifreeze coming out all over the highway.
[/quote]


My missing upper gasket is probably the reason I can run that cardboard in 50-60 degree temps.

The new Radiator, water pump fan and heater core are probably the other reasons.

 

[Poser]

Oh, and it is not an O-ring, in the traditional sense of an o-ring, it is a square cut ring 1/8"thick by 1/4"wide by 2" overall diameter.

I have seen some veriations from maker to maker(Toyota vs. aftermarket)
so something "close" would probably prove to be better than nothing.

-Steve

 

[Cruiserdrew]

Geez-the one from Toyota only costs about $2 and it fits and works perfect. Get it, and be happy...and warm. NAPA sells one too, which I have used as well. The lower gasket that NAPA sells does not work-it is too thick.

 

[offcamber40]

I am having the same problem with mine. I picked up a new heavy duty radiator and thermostat.. what I found was that different companies sell different temp thermostats for what they feel is the best running temp.. the new one I got is 10 degrees cooler than the one I pulled out.. kinda annoying if you ask me.. If I ask for a factory thermostat I expect to get a factory spec stat.. You might want to check the temp on yours, it fixed my problem.

Mike