Paul L

I have read recent threads on the fail-safe t-stats. People seem to like them. I looked at one today (MotoRad) and carefully read the fine print. Once they are triggered (at an unspecified temp) they are toast and have to be replaced. What is their advantage beyond a good quality Stant?

Comp Cam 1

I would imagine to get you home. and install another one?: I believe the person below me is correct.

66427-450

I would guess the fact that if you experienced (the most likely) failure, it would result in full coolant flow, as rather than?, perhaps no flow?.

Hitch

A fail safe thermostat like a Robert Shaw is called so because it fails in the open position. This does not mean that if you get it to a certain temperature it will fail and then it will never reset. The fail safe thermostats require no spring pressure to hold them open the operation is that cool temperature holds it closed and as it warms up the spring releases. At least that's the way that I've come to understand them... Dave

ghostrider20

I have never seen a T-stat fail. They have been stuck shut on motors that have sat for a lenght of time 1-2 years. Just my experiance.

MikeM

'What is their advantage beyond a good quality Stant?'

The only advantage I see is it gives you something to talk about on these forums. I've been around the block more than a few times and I've never seen one fail. Next time around the block? Who knows?

I think all my cars are in good mechanical shape and I believe I keep them that way. However, I do not subscribe to the "Chicken Little" preventive maintenence theory whereby you have to keep you wallet emptied making sure you haven't left anything to chance because of what "might happen".

I prefer to keep an eye on what's likely to happen.

wmf62

my Delco thermostat failed 'closed' last week. BIG mess...
Bill

magicv8

Robert Shaw tstats are not fail safe. They are balanced. Ask the manufacturer - I did.

Fail safe tstats are almost pointless on an A-C car or any other car with wide swings (30 degrees or more) in temp. I asked the (motorad) manufacturer of those too.

Plasticman

A "fail safe" (from MotoRad) will indeed lock open as stated previously. Please read the following from their website:

What's in a cooling system?
MotoRad's Fail-Safe® thermostats are a major technological advance in the design, manufacturing and use of automotive thermostats. The Fail-Safe® has been developed to work the same as a conventional thermostat regulating the temperature of the engine and when an overheating occurs the Fail-Safe® protects the engine by permanently locking fully into the open position, thus allowing coolant to continue to flow from the engine to the radiator.

Here is their website for the full details:

http://www.motoradusa.com/news/20020630.html

I use Robert Shaw (now sold by Mr. Gasket, Milodon, Flow Kooler, EMP Stewart, and "maybe" Be Cool). Very accurate and balanced flow (this means they do not try to shut closed with increased flow). But I have seen nothing that says the Robert Shaw design will fail "safe". Here is the write up from Milodon (off the Summit website):

"Cooler is better.
High-flow thermostats from Milodon greatly aid the correct functioning of a high-performance cooling system. They're engineered to warm the engine to a proper operating temperature without making it run hot enough to lose power. Also, the "Balanced Sleeve" design equalizes the pressures exerted on the thermostat. This counters the undesired effect of increased flow from a high-volume water pump, which actually tends to hold a stat closed."

Here is the Mr. Gasket write up off the same website:

"High-flow temperature control.
Mr. Gasket high-performance thermostats are designed to resist large variations in coolant pressures that can occur at high rpms. Under these conditions, coolant temperature and pressure fight for control of the thermostat, keeping it from opening at its designed temperature. These balanced high-performance thermostats feature brass-and-copper construction, and open at the right temperature regardless of engine rpm."

The Be Cool thermostat does say it will fail safe, but is does not look like the same design as the "MotoRad" version. In fact it looks to be very similar to the Robert Shaw design. Here is their write up from Summit:

"Don't take chances with engine cooling.
Be Cool's high-performance thermostats provide accurate temperature control, as well as excellent coolant flow. However, perhaps their most important feature is that if they should ever fail, they will do so in the open position. That will allow you to make it to a safe location without damaging your engine."

The EMP Stewart thermostats are made by Robert Shaw (and sold by Summit), but are modified by EMP Stewart. Their write up does not say what they do differently, and says nothing about being Fail Safe. Here is their write up:

"Trust your cooling system needs to EMP Stewart Components!
These EMP Stewart custom thermostats are manufactured by Robert Shaw and modified by EMP Stewart. They feature a balanced sleeve design and are designed for high-rpm applications. These high-flow thermostats are recommended for any performance applications and work well with high-output water pumps."

Plasticman

00fxd

I had delco one fail me too last month. Less than a year old. Drove me crazy looking at other stuff till I finally boiled it on the stove. Would barely open @ 225deg. Checked a new one and it opened right on the number.

MikeM

Are there any OEM's that use a "fail safe" thermostat? That is just one indicator. They have to stand the warranty.

Paul L

Thanks to all for the replies. I'm not entirely sold but may try one.