• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

Robert Shaw thermostat too cold

flousberg

Sr. Member
Joined
Apr 28, 2002
Messages
742
I have had this problem in the past with high flow thermostats. I installed a Robert Shaw about 6 weeks ago. If it is not hot out or working it hard, the temp never comes up to 195. I have had this problem before with these type of thermostats, either Robert Shaw or Mr Gasket. Has anyone else seen this? Yesterday coming down the mountain, it was as cold as 150. This obviously is not right. I have gone through 3 of these over the years. I think I am going back to a standard thermostat.
 

SHX669

Bronco Guru
Joined
Jan 9, 2009
Messages
1,997
I've had that issue with the Mr Gasket Hiflow T stats ; they never seem to fully shut off.
On the other hand I've had great luck with the Robert Shaw Hi Flow t stats . The only issue I have with them is currently the only temp rating they make for the" Cleveland" is 195*, but they do have a 180* for the Windsor.
Shx
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,960
'88 mustang stock replacement thermostat. High flow and will warm up.

I have had the same issues with the Robert Shaw thermostats as well. It is like they have a very wide tolerance for opening, they crack open very early. Being high flow they only need to open a little to get cooling.
 

bronco1969

New Member
Joined
Nov 28, 2010
Messages
26
Loc.
Candler,NC
The hi-flow thermostats have bypass slots around them to equalize the pressure,so they are never really closed.Stock type t-stats wouldn't work for me but I got a Stant Superstant t-stat that fixed all my problems.I tried probably 8 different t-stats including robertshaw/mr gasket before the superstant fixed it.
 

clarrance

Bronco Guru
Joined
Mar 3, 2005
Messages
2,674
Would these symptoms cause overheating in traffic too. I'm running a 195 If it is 85+ outside it will stay around 190, but in traffic it will creep up around 210-220. If the temp outside drops around 75 or below outside mine will run around 160, and never get up to 195.
 

Lennardlector

Contributor
Full Member
Joined
Mar 21, 2010
Messages
178
Not likely, I had issues with all the above as well on various vehicles. 9/10 the Robert shaw did work some parts might have had bad batches. In the end I just use a stock tstat and drill (3) 1/8 holes for the "bypass" effect.

Back to your symptoms with overheating it sounds to me like your water pump is going south.
Start small, I.e; cheapest route.

Change tstat

Check hoses make sure they are good and don't collapse at high speed

Make sure radiator is operating at right temp, get a cheap laser thermometer and make sure one end is cooler than the other and at respective temps.

Check for blockages/rust and gunk build up, flush system.

If no bueno get a high flow pump.

Sure a stock pump is fine, they've been using them for years, I don't know about you but I don't drive 55 with 29inch tires so spending the extra 50 on a high flow is worth it IMO.

The only other cooling mod I did was put springs I the lower hose cause it was collapsing from the extra flow.
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
Xwhatever on the bad high flows. I've had the same issues. In winter or when in the mts the thing would never reach operating temp. Go back to a standard tstat and you'll be fine.
I really dont feel that high flow water pumps are needed in a bronco because the cooling system is pretty small. If you were running a tripple pass radiator then a high flow pump would be a benefit but other wise I think they are more of a waste of $$.
High flow water pumps make more of a differance at low RPMs than high RPMs. The hi flows were actually made so you could underdrive your water pump and still have the same flow. Some stock setups do underdrive the water pump to begin with others overdrive them so you really have to check sometimes little more than a pulley change can make a differance.
The driving 55 with 29in tires doesnt compute. sure broncos were designed more or less when that was the speed limit. But you take todays speed limit 75mph and 33in tires and your spinning the engine even faster. 2300 vs 2700 with 3.50 gearing.
 

Socal Tom

Bronco Guru
Joined
Feb 12, 2004
Messages
2,442
Loc.
San Diego, CA
Would these symptoms cause overheating in traffic too. I'm running a 195 If it is 85+ outside it will stay around 190, but in traffic it will creep up around 210-220. If the temp outside drops around 75 or below outside mine will run around 160, and never get up to 195.

Yes,
Cooling systems behaviors are very complex, but too cold a thermostat can lead to overheating in traffic.
Tom
 
OP
OP
flousberg

flousberg

Sr. Member
Joined
Apr 28, 2002
Messages
742
I am going to change it out tonight. Back to the stock thermostat from ford.
 
Top