47-55.1 hot 305 post radiator swap

[Mrs E7]

Good day all ..

Having a bit of an issue getting my head wrapped around a potential overheating issue...

I'm thinking I may have a bad new thermostat, or maybe should not have used the felt gasket and the rubber O ring gasket combined when replacing the thermostat, or my water pump is taking a siesta, or my temperature gauge just reads low.

Notes on what I have, and have done ...
Apologies for the length of the post, as I tend to include a little more than what I think might be the direct pieces/parts in the event things I think might be unrelated are actually related...

I'm fairly mechanically inclined, learn fast, but don't have a lot of exposure to engines other than my '62 Corvair Rampside, so I'm in a bit of a learning mode with a recent acquisition of a '49 3100... as such, I am stumped by what I thought would be an easy radiator swap ...
(famous last words.. I'm aware

Prior to purchase, the 305 in it actually was running very well .. albeit with signs of an exhaust leak .. cab floor is of Fred Flintstone nature, so it almost required a respirator... but I wasn't sure where the leak was coming from.
...temp gauge appeared to work, as did the radiator .. but of course 2 miles after $ exchanged, the gorilla glue the seller apparently used on the radiator broke loose ..

To get a running start at knowing what I am working with, I performed the following ...

- changed oil / filter
- changed fuel filter and hoses
- new fuel pump
- new fuel tank
- new fuel
- changed transmission fluid / filter
- flushed water jacket with distilled water .. old fluid drain and flush were surprisingly clean
- new radiator (from 2 core to 3 core Champion CC5100)
- new upper radiator hose - flexible steel
- new lower radiator hose - rubber
- 2 gallons of 50/50 Prestone *
- new water inlet housing (old one was crusty)
- new thermostat (180)
.. this came with both a rubber seal and a felt gasket. I used both after cleaning/scraping the intake surface thoroughly.
- checked/tightened/replaced as necessary all hose clamps/fittings I could get to

* I got a hair over 2 gallons of 50/50 in the radiator intending to get it to temp and top it off.

Engine started right up after fluid swaps.
Exhaust leak seemed reduced, no idea how, but there was no exhaust in the cab .. seemed to be from the passenger side pipe, behind the cab only now (haven't looked closely yet) ..
.. ran it a few minutes .. temp gauge got to about 140/150
- checked/topped trans fluid ....
- turned off and let it cool down for about 20 minutes ..
- checked oil
- radiator was still cool to the touch, but it had pressurized as evident by the nice fresh green spew as I removed the cap ..
... ran it a few more minutes..
... temp came up fast to 180, 190 .. got just shy of the 200 mark .. but I honestly don't know if the gauge is accurate .. needle raises from dead to just below the first mark of 100 with key in ACC ... which is the same amount of needle movement in the oil temp gauge.
... exhaust leak seemed to be worse and entering cab .. again, no idea how/why
- turned off
... radiator hot to touch .. upper hose hot .. forgot to check lower hose
... carefully/slowly removed the radiator cap with gloves and towel ... coolant was bubbling/steaming slightly.
... water pump very warm to touch, but I'm not sure how to know if this is working properly


My next step would be to make a mess with coolant and remove and test the thermostat, but I would love to hear from anyone with any thoughts on anything I missed or could/should do.



BONUS POINTS FOR INTEL
----------------------------------
I read something (quoted below) about the EFE valve that may be completely unrelated, but would appreciate any insight on this as well .. especially since I'm assuming the 'right' side engine components are the passenger side, and might imply this is not my issue.

--------------- EFE VALVE ----------
The purpose of this valve is to close when the engine is cold and re-route the exhaust gases from the right cylinder head back up through the head and through the bottom of the inlet manifold and out through the left hand head and left hand exhaust manifold.

When the water in the engine gets hot enough a TVS in the thermostat housing opens and directs engine vacuum to open the EFE valve and allow right side exhaust gas to flow out the right exhaust pipe.
--------------- // EFE VALVE ----------




Thanks in advance for any suggestions/ advice
- Wendy

PS:
I am very thankful for a place like this to post my garage drama .. if nothing else, it helped me recap in my mind that I believe I did everything properly, and just have a gremlin to catch.


====================
BUILD DETAILS TO DATE
====================
'49 Chevy 3100 Truck
- 305
... old headers (I originally incorrectly posted I had old iron manifolds)
- 700R4
- power steering
- front disk brakes / rear drums
- new Champion Cooling Systems CC5100 3 Row Aluminum Radiator
- new upper radiator hose - flexible steel
- new lower radiator hose - rubber
- new fuel pump
- new fuel filter
- new fuel tank
====================

[joedoh]

I wish you would have checked the lower hose.

I have had a bad thermostat right out of the box, if you think of the millions that are made and even a failure rate of a tenth of a percent is still a bunch.

but I am not sure its bad. every time I replace a radiator lately it seems like I need to "burp" the air. so the temp spikes, sometimes over 220, then settles down.

also remember that a 180 thermostat doesnt mean the engine runs at 180, thats just when the thermostat fully opens. the engine could run at any temp higher or lower than that. modern engines run closer to 200 in my experience.

dont forget the overflow system. I had a friend do some work on a truck and he gave it back saying "it runs fine but its getting hot". well he had plugged the overflow line. the way an expansion system burps, is while running at temp the air goes out the overflow line into the overflow tank with a couple inches of coolant in it. then when cooling down it sucks the fluid back in through that line if you plug the line, air cant escape (air is steam, steam is over 212 degrees), and so the engine just perpetually runs hot. incidentally he plugged the overflow line because it was "leaking". not quite!

[MiraclePieCo]

With what you've said so far I'm cautiously optometrist that you don't have an overheating problem at all. I suspect your temp went to 200 just because there was hot water simmering in the block for 20 minutes without benefit of going through the radiator after you shut the motor down.

BTW, I always use a "Spill Free Funnel" when changing coolant. It enables one to burp the air from the system and perfectly set the right hot coolant level.

https://www.lislecorp.com/specialty-...ree-funnel-606

[dsraven]

with all the bad aftermarket thermostats I have installed over the years I only use an oem stat now. no problems with them so far. some stats have a bleed hole built into them to allow air to escape.
the water outlet housing should just have the stat sitting in the recessed area of the intake and then the housing has a gasket under it when it goes on. the rubber ring style is usually used on newer style engines and the ring has a slice in it to fit around the outside of the stat. not usually using both but if it works, didn't break anything and doesn't leak then I guess you win.
do you have a heater in the truck? check the heater hoses to see if they are also hot, both of them, so you know the heater isn't storing a bubble of air.
I usually squeeze the upper hose to burp the system on units that have trouble getting all the air out. let it sit overnight and check the level when it is cold. if using the stock style rad with the large upper tank the level should be down from the neck some but for sure covering the ends of the rad tubes. I find they usually find their own level after burping some out. if you have an overflow tank you will need a different style of rad cap that has the rubber gasket under the top part to seal the cap against the rad neck.an overflow tank is a good idea because then the system can draw some fluid back in when it cools off and the fluid takes less volume than when it is hot.
you can use an el cheapo deluxe thermometer on a rad or heater hose to get the temp. you can also buy a better gauge and install somewhere discreet, like in the glove box or something, if you don't wanna see it all the time, or simply install it for a short time until you get a bead on what your cluster temp gauge is reading compared to actual.

[Mrs E7]

Thanks for the responses..
I wish I would have checked the lower hose too.. I ALSO wish I had checked the thermostat I was sold before I put it in. Took it out to test and although the box says 180 .. thermostat says 195
Got a new one .. putting it in today and will report back.

Thank you again for the sounding board and experienced responses.

[geezer#99]

Make sure you put the thermostat in in the right direction. The spring side goes in the intake.
Do you have a fan shroud?
Do you have a return bottle on the rad overflow?

[MiraclePieCo]

Originally Posted by Mrs E7

Took it out to test and although the box says 180 .. thermostat says 195

YIKES! Important information! That could be a big factor!

[Volfandt]

Keep in mind that extended idling will cause an engine to run hotter than when it's got increased air flow through the radiator at speed. This holds true for both mechanical and electric fans.

The bubbling could be the air getting purged and steam is SOP.

Definitely try a 180. And for GP if you still see higher temps when extended idling in your garage (or where ever your testing) put a fan in front and have it blow additional air across the radiator and see if it drops.

[dsraven]

ok,
49 chevy with 305
is this a stock frame or a swap frame? I ask because some swaps have an off center rad-lower than the regular stock 350 mechanical fan would be-so some would say the airflow through the rad is compromised with a stock mechanical fan system
if mechanical fan, does it run all the time or does it have a temp sensitive fan hub? how does the fan line up with the rad, is there a fan shroud? is the grille restricting air flow?
a few pics of under the hood may help.

[Mrs E7]

thanks again for all of the intel !
I put an actual 180 thermostat in it and viola !
may have been a combination of that and burping some air out .. in any case, it is working now

though the issue is resolved, I will acknowledge some inquiries as the entirety of this thread has been educational and I appreciate the extra bits and pieces ..
.. I did have it in correctly
.. no fan shroud .. no hood on at the moment either
.. very large mech fan
.. no overflow tank yet ... port is open
.. frame origin is unknown, but the core support at least seems to be that of a '49 .. and it is centered

On to track down the exhaust leak..

[oldman3]

Glad you were able to get it resolved...Jim

[mr48chev]

In all actuality, it is more of a feel good thing with old truck owners that the temp gauge doesn't rise above 185 or so rather than a necessity with a late model engine and a radiator that will handle higher pressures.

I know 3/4 of these guys pee on their shoes out of fear if the temp gauge with a 305 or 350 hits 200 but that was normal operating temps for the later car that the engine came out of. The engine ran at 200 plus for years on end in the vehicle it came in without an issue but when a guys sticks it in an old truck it all the sudden is "OH craP my engine is running hot" It isn't puking coolant when you stop but the gauge scares the daylights out of you.

[1project2many]

Ford solved the problem of people worrying about engine temperature by taking numbers off the gauges. C and H is all you get.

[joedoh]

my daughters mini cooper didnt even come with a temp gauge. which is fine for her because it could be a 7" dial with fluorescent numbers and a flashing light and she wouldnt notice.

Originally Posted by MiraclePieCo

I'm cautiously optometrist

I know this is an autocorrect bumtangle but I cant help but think of a timid eye doctor "well you MIGHT need glasses, oh I dont know"

[MikeB]

Originally Posted by Mrs E7

ran it a few minutes .. temp gauge got to about 140/150
- checked/topped trans fluid ....
- turned off and let it cool down for about 20 minutes ..
- checked oil
- radiator was still cool to the touch, but it had pressurized as evident by the nice fresh green spew as I removed the cap ..
... ran it a few more minutes..
... temp came up fast to 180, 190 .. got just shy of the 200 mark .. but I honestly don't know if the gauge is accurate .. needle raises from dead to just below the first mark of 100 with key in ACC ... which is the same amount of needle movement in the oil temp gauge.

Nothing wrong with any of the above. And 200 is OK, especially with no fan shroud and the truck sitting still.

Also, I've read where 185 is the minimum an internal combustion engine wants for optimum efficiency. What's worse than 200 degrees in the summer is an engine that doesn't get above 160 or so in the winter. That sucker would use extra fuel, make less than potential power, and be a water vapor maker.

[1project2many]

Originally Posted by MiraclePieCo View Post
I'm cautiously optometrist


I know this is an autocorrect bumtangle but I cant help but think of a timid eye doctor "well you MIGHT need glasses, oh I dont know"

I didn't want to point it out. With the add-on jokes the thread would become bifocal.

[mr48chev]

I'm thinking that if you do some investigating into what the OEM recommended thermostat is for that 305 in the vehicle it came in from the factory you will see the standard thermostat for the application is 195. That is probably why you got a 195 thermostat when you went in and asked for a thermostat for a 19___ Chevrolet ____ 305 telling them what donor car the engine came out of when ordering the thermostat. Unless you specifically asked for a 180 that is.