Nice tidbit for those with barely any heat

[darrenryall]

i bet if u dont have heat its the vacuum to the door if u have one, or the wire running to the door to let the heat in.

i just replace some odds and ends in the car today, removed heater core and using a jumper outside the car made out of 1/2 copper pipe welded in untill i get this thing replaced.

no leaks which is kool right now

Reformatted to make sense for me, you nearly broke my graamer centre dude..

So you fabricated a heater core? How's it been working?

[squeethebee]

So this may be a silly question, but what is the difference between the Ford part, and a Motorcraft part?

ed

[JohnGunn]

So this may be a silly question, but what is the difference between the Ford part, and a Motorcraft part?

ed

Ford calls their parts Motorcraft. Motorcraft spark plugs, filters, thermostats, etc. are what you would expect to get if you bought them at the local Ford Dealer's parts department.

John Gunn
Coronado, CA

[JohnGunn]

Great Thread

This is one of the most helpful threads I have found on this forum. First, it is focused on a single important part, the thermostat, that sooner or later everyone is forced to deal with. And, second, all the comments are devoted to that topic without much distracting information. It has the quality of a wiki which is a page or group of pages dealing with a particular topic which readers are allowed to edit and add corrections and additions. I could imagine a FordFestiva.com wiki with a page dedicated to each part on a Festiva.

Whenever someone needed to deal with a particular part he would check to see if there was already a page for that part and, if not, he would start one. Of course, if he found a page for that part had already been started he would read it and add to the page whatever he learned from his own experience. No pages would get lost among the results of a long search list because there would be only one page for each part. Over time, with the expertise of the people on this list, the usefulness would soon become head and shoulders above any existing manual. I can imagine nothing that would help preserve and perpetuate the legacy of this find automobile more.

Suggestion: When I want to look for information on a particular part I will search for the name of that part in the thread titles only. I added "thermostat" to the tag list of this thread, which was empty, but since tags are rarely used I would like to suggest that the word "thermostat" be added to the title of this thread. I really think information in it is too valuable to be lost because its title doesn't give a clue to its real topic.

My attempt to improve this fine thread follows the following three quotes.

Here are some photos of the OEM thermostat for an '88 B6 which uses the same as the Festiva's B3. I picked this one up from a local Mazda dealer for about $25.00CD. I bought this quite a while ago and forgot to record the part number ops:

http://i71.photobucket.com/albums/i156/fastivaca/IMG_6045.jpg

http://i71.photobucket.com/albums/i156/fastivaca/IMG_6037.jpg

http://i71.photobucket.com/albums/i156/fastivaca/IMG_6039.jpg

Hope that answers some questions.

The aftermarket t-stats don't have the second valve on them.

Got a Question....on the new Thermostat should the small valve go towards the top...or doesn't it matter?

yes, to the top, and yes, it does matter.

I looked up installing a thermostat in the three manuals I own, 1990 and 1992 Ford Service Manuals, and the Haynes manual. The service manuals say that the sub valve should be placed at the top when installing, but the Haynes says to install it "with the small bypass hole in the thermostat at the high point (top)." In the referenced photo the instruction is slightly different. "the bypass hole (arrow) up ( or subvalve on later models)"

From fastivaca's second picture, above, it looks as if the two stage thermostat has both a bypass hole and a sub valve. At first I thought that Slant had just replaced the sub valve with a cheaper bypass hole, but now I am wondering what the function of the bypass hole is. I assume, since the sub valve is made to open before the main thermostat valve, that it should be at the top where the hotter water will warm it first. But I wonder what the bypass hole accomplishes? I'm sure it wouldn't be there if the designers didn't think it important.

Can anyone explain the actual functional benefit of the two stage thermostat and what the bypass hole does. Knowledge appreciated, but speculation also welcome.

John Gunn
Coronado, CA

[MTec007]

i got one now just got to put it in.

[jm75lah]

The bypass hole goes to the top to vent air while filling the cooling system. The sub-valve opens before the main valve to limit coolant flow to the radiator to maintain engine temp. As the thread noted it also improves heater performance. Thermostats also increase coolant pressure in the engine improving heat transfer. The sub-valve allows cooling while maintaining pressure in the engine and heater core. I did not look up the coolant capacity specs, but the radiator probably holds as much coolant as the engine.

[micah]

just wanted to chime in here and say that i recently did my timing belt and water pump. installed the OEM mazda/ford thermostat and my heater started working. also noticed the temp gauge get up to halfway whereas it had previously only gone up about 1/4-1/3. definitely worth swapping out if youre having issues.

[1988redfordfestiva]

i'm using a fail safe 180 from autozone i actually tested mine i have heat and fan is running sensor says alittle above c but if i plug the fan in it gets even hotter but temp runs in the middle and fan kicks on for like 2 mins then shuts off when temp starts to rise but i unplug it just for summer for now when winter comes will plug it back in

http://www.autozone.com/autozone/catalog/parts/partsProduct.jsp?itemIdentifier=139160_0_1632_93208&skuDescription=Failsafe+/+Thermostat&brandName=Failsafe&displayName=Thermostat&categoryNValue=14299999&sortType=&store=5066&isSearchByPartNumber=false&fromWhere=&fromString=search&counter=3&itemId=47-0&navValue=14200047&filterByKeyWord=thermostate&productId=139160&searchText=thermostate&categoryDisplayName=Routine+Maintenance&parentId=42-0

[milehighbear]

This was a very good thread. I even put it in my favorites. I was having trouble and got the number off of here for mazda stat and put it in. Heat is working great. One thing to remember, on the mazda stant, there is a small arrow that shows which end goes up. It will go in two different ways so using arrow helps. Plus i superglued stat in place before i put housing on, works great. Thank you all for comments and words of advice.

[fastivaca]

Tried to buy one from Ford today.... here's the result.

http://www.fordfestiva.com/forums/showthread.php?t=28721

[Festiva Time]

I have always run the single-stage Thermostats on my '88 Festiva [R.I.P.] and now with my '90 Festiva, with no problems. Maybe in harsher winter climates it would make a difference, to use the 2-stage Type.

[ENEMY_]

Okk, I've read almost all this and I'm still lost(not mechanically inclined)

My needle on the dash never really moves above the bottom line unless I'm stopped. My vent's do not blow heat and the defrost dosn't blow very warm.

What should I do? Replace thermostat? Or how do I flush the heater core or whatever?

[JohnGunn]

Okk, I've read almost all this and I'm still lost(not mechanically inclined)

My needle on the dash never really moves above the bottom line unless I'm stopped. My vent's do not blow heat and the defrost dosn't blow very warm.

What should I do? Replace thermostat? Or how do I flush the heater core or whatever?

I sounds very much like your thermostat, if, indeed there is one installed, is stuck open. But, before you start taking things apart, it would be helpful if you spent some time looking at your engine to see how the cooling system is constructed.

You will see the radiator and the two large hoses that connect it to the engine. On the firewall you will see two hoses that carry coolant into and out of the heater core. On the engine side of the radiator you will see the electric cooling fan. The thermostat is located at the point where the top radiator hose attaches to the engine. There is, of course, a water pump which is out of sight under the timing belt covers. But when it fails it usually signals that by leaking from the passenger's side of the engine.

Here is the link to something I wrote a while back listing the thermally triggered events within the cooling system. It tells you how to judge whether your thermostat is stuck open or not.

http://www.fordfestiva.com/forums/showpost.php?p=314708&postcount=11

The most common cooling system problems are failing thermostat and restricted coolant flow through passages within the system. Problems with the cooling system should be addressed by first replacing the thermostat with a good quality, not necessarily from Ford, two stage thermostat. If you were to hold both the two stage and the cheap one in you hands the difference in quality would be immediately apparent. The complexity of the OEM part is the product of careful design. Not the sort of thing one should toss out without a second thought.

A cool running engine is critical to the long term reliability of your Festiva. Every minute the engine overheats the gaskets and rubber seals harden and move in the direction of leaking. The cost of a good thermostat is a small price to pay to prevent that.

There are chemical flushes that are designed to clean out the passages within the cooling system. In addition to that it is helpful to back flush the system, including the heater core. Prestone makes a cheap connector that can be spliced into your system that eases the back flushing process. I've never had occasion to use one, but someone who has may perhaps comment on it.

Go around to the exposed parts of the system using your hands to judge the temperature of the various components. You can even remove the grill and use your hand to judge the flow of hot coolant through all parts of the radiator.

It sounds like your problem is not critical, at least not in the warm weather, so you can take your time, study your manual, "touch test" the exposed parts on your engine, and, then, move on from there.

John Gunn
Coronado, CA

[g3ride69]

i have found this very informative.... thanks for the part #'s. what is the best bet for a thermostat housing... yep i broke mine (broke while removing.... bunch of atv or similiar stcky stuff was working too well)...

junk yards are not too great around here in south dakota.... is there an aftermarket housing? (summit has small block chevy housings for 5$).

any replies or private messages are appreciated!
1988 festiva lx carb (silver with red orange and yellow hot rod flames)
g3ride69

[GenevaDirt]

i have found this very informative.... thanks for the part #'s. what is the best bet for a thermostat housing... yep i broke mine (broke while removing.... bunch of atv or similiar stcky stuff was working too well)...

junk yards are not too great around here in south dakota.... is there an aftermarket housing? (summit has small block chevy housings for 5$).

any replies or private messages are appreciated!
1988 festiva lx carb (silver with red orange and yellow hot rod flames)
g3ride69

hello...if no yards are around then posting a [WTB] in the sale section would be your best bet....add your location to your profile when you get a chance....helps bunches. Welcome to the site.