How important is it to put a Motorcraft thermostat in an Aerostar?

it's a 97 with a 4.0 and 250,000 km.

i put a bone-yard one in over the summer and now that the snow is here the pesky brat won't warm up.

so, how important is a good thermostat ( scale of 1-10 )

how good is a motorcraft thermostat ( scale of 1-10 )

how well do the aftermarket ones stand up.. please rate them according to your experiences or the opinions of your most experienced wrenchers.

thanks!

 

A good thermostat is very important (9 from 1-10) as keeping the engine operating in the correct temperature range is very important. The EEC needs to see a certain temperature in order to properly control the engine. Also, the engine itself wears better when run at the correct temperatures.

The original thermostat in 4 liter engine failed by sticking open like your junkyard special, and the engine would not warm up properly even in the mild southern California winter. The gas mileage was horrible during those times.

I got an aftermarket model from Robert Shaw, which is supposed to be pretty good, though not spectacular one way or another.

The only problem with aftermarket thermostats is that they do not have the exact temperature rating of the stock Ford model. For example, Ford's are usually rated at 192F, but the only aftermarket models you can get are 190F or 195F. Since it's worse to have the engine run too cool, I got the 195F version.

 

I use the Stant SuperStat® Thermostats. smooth operation with no rapid changes up and down while cruising on the road or hill climbing. the Aero has had one since i replaced the OEM. use the 195 in the Aero
have used them in several rigs for the past 20 years. never had a Stant Premium Superstat fail, they look the same when I change as the day I put them in.
have used the Motorcraft with no failures.
the Motorcraft for the Aero is rated at 190d F.

have had problems with other brands years ago, sticking open closed or falling apart.

the 4L Aero with rear heating can trap air and not purge completely. creates air pockets in the engine. will cause wild swings in temps and gauge. park nose up on hill and let run hot with cap off and both front rear fan and heat on high. helps air purging.

check out Rock Auto dot com our site sponsor for prices and quick delivery.

Stant
Unlike conventional thermostats that continually open and close to achieve the proper operating temperature and flood the engine with coolant, the Stant SuperStat® thermostat has a patented v-notch, non-linear design that reduces cycling by precisely metering the amount of coolant needed to maintain proper operating temperature.

The v-notch provides a small inital flow. As the engine heats up, the v-notch gradually opens wider, metering coolant into the system until the desired engine temperature is reached.

 

I have used Stants, won't go there again. Their premium thermostat lacks the air bleed valve, so its harder to purge air out, and it does not open and close at the correct temperature. The cheaper one has the valve, but also does not open and close at the right temperature. Through RockAuto, the Motorcraft doesn't cost much more than anything else, and it fits and works correctly. I went through 2 Stant Superstats in 20,000 miles cause they kept overcooling. I had problems getting the air out with the Stants, largely because they lacked the air bleed valve. The Motorcraft one gave me no difficulty with getting the air out on either my or my mothers 4.0L with rear heating and AC.

I would go for the Motorcraft one hands down.

I would rate having a good thermostat as a 9 out of 10, and the Motorcraft thermostat I would rate as a 10 out of 10. The Stant, I would give a 6 out of 10.

 

I haven't had much experience with the Aerostar's thermostat...only just replaced it with a Motorcraft one, but since I've had 2 other cars that I've nursed to about 200,000kms, and replaced the thermostats a few times in each, so I think I know a thing or two.

My findings are that the one from the manufacturers seems to be able to react faster to rapid heat buildup - there's less of that "cool one moment, boiling the next". If you are climbing a big hill with a load, in humid conditions (like I do once a year for the family's annual camping trip - 90 Degrees F is the norm) the temperature gauge's climb up is much more linear.

I had a Dodge 600 with a cheap temp sending unit and regretted it...it would go into the red with lights flashing...then cool down. I had a VW Fox and it too did the same thing....when I replaced both with their respective manufacturer's thermostats, I had no problem - it got warm, but never to anywhere near a critical level, and this is in extreme conditions.

 

Funny that the original thermostat in my Mustang failed in the mode where it stuck closed. So most of the time I would watch my temperature gauge climb slowly toward the red zone. It wasn't until I went to the desert one summer, when the gauge actually touched the red zone before it suddenly dropped into the normal range. I replaced it with the Robert Shaw model, and it's been fine, for about 10 years.

 

the Stant Premium stainless steel uses the V notch opening to air bleed when cold and closed instead of a jiggle pin design.

the 4L Aero with rear heat is especial difficult to air bleed. park on hill with nose up at least 2 ft above tail. cap off when cold. run until hot and goose engine up and down with both front and rear heaters and fans on max.

 

the Stant Premium stainless steel uses the V notch opening to air bleed when cold and closed instead of a jiggle pin design.

the 4L Aero with rear heat is especial difficult to air bleed. park on hill with nose up at least 2 ft above tail. cap off when cold. run until hot and goose engine up and down with both front and rear heaters and fans on max.

 

what's technically important about the Stant Premium V notch is that it allows more initial coolant flow in the first few minutes after engine start.
prevents hot spots on cylinders and heads.
the thermostat is the next to last thing in the coolant system to heat up

coolant flow and no hot spots in these thin block and head engines is critical.

I've not had any problems purging air out of the coolant system in my Aero or the V10 Ford motor home with dual rear heater I used to have, had hoses at least 20 ft long. both ran Stants

 

I've used them all in my 3 96's. I still have the up down thing in the blue one. The white one is good and so is the green one..I went through 3 in the blue van after I did the intake set. The motorcraft seems to be not much different from the rest..I wish I could figure out why the up and down temp...I'm guessing its the water pump which I ain't gonna change till it goes bad..There was a tsb about that..

Dick

 

That V-notch was probably contributing to the overcooling problem that I experienced. Still, the thermostats opened over 30 degrees cooler than the posted temp. This resulted in terrible gas mileage and performance. The Motorcraft one has given me no problem, the original lasted about 130,000 miles on my van, the Stants seemed to work correctly only very briefly, less than a week.

 

Currently have the motorcraft in the blue van and stant prem in the others.

 

I have had my current '97 for 2 1/2 years - this will be my third winter with it. It never warms up in the winter, so the past two years I put cardboard in front of the radiator for the winter.

That worked fine, but obviously my thermostat is stuck open, which no doubt also has an affect even in the summer. So yes, in an ideal world I would replace it.

The question is: I am tight on money and time. I could get a new one for peanuts from Rockauto, but will probably never find the time to put it in. Is it worth having a mechanic do it? I have a mechanic that is not very bright on diagnostics, but is totally honest and cheap. Basically I tell him what to change (sometimes I even supply the parts from Rockauto closeouts) and he just charges me labor costs.

How difficult is it? I need to know in case I try it myself, or to guess how ling it will take someone else to do.

Also, how important is it? Should I just go with the cardboard? Note that even with cardboard, the engine starts off in a high-idle warm up mode, and does not slow down for about ten minutes in the winter. It makes it harder to control when the idle is so high, as it bucks against the brakes at traffic stops.

 

Odd. I checked RockAuto, and they have none that are 192 degrees. The ones that they have marked "OE Temperature" are all 195 degrees.

Then I checked AutoZone, because there are some in my neighborhood. Unfortunately all of them say "Special Order" - which is not terrible, but it does add up to two weeks to the time frame, and is not returnable. They have ones that say OE Temp at 192 degrees.

Also, once shipping is factored in, AZ might cost me the same anyway.

Rock had so many, that I cannot figure out which one to get.!?!

 

195d F is the stock OEM thermostat temp and what the PCM programming parameters are written for.
15 minutes of work, 3 small bolts and one hose clamp. need some gasket sealant for the seal and a scraper to clean the old gasket off.

can even reuse your coolant, only have to drain out a couple quarts or so out the bottom of the radiator to prevent coolant from pouring out over top of engine from thermostat housing/hose.

i would not risk a cheaply built/designed NAPA Autozone local store Chinese brand. Motorcraft or the Stant Super Premium stainless steel only.

good time to reverse flush your heater core with garden hose, keep pressure below 30 psi or risk blowing out the core. should be good flow with little to no back pressure. will probably have to vacuum fool the heater inline coolant flow valve.