A slightly different thermostat question

[Mike McKown]

Now if we had xray vision to see in the block, or the next best thing a hand held pyrometer......

After sitting there idling for ten minutes, you can put your hand anywhere on the head (away from the exhaust) and it's not very hot.

[m715]

Exact same as I wrote about before. His just finally broke loose and began heating after two years of flushes Etc. The blockage must locallize itself in a place easily bypassed by coolant flow, and allows the engine to stay cool without picking up enough heat to warm the stream. Wish I had a REAL solution..... I still wonder where it could do both?

Michael

[ericsmith32]

Add a capful or so of MMO to the radiator. It's a bit harsher than the citric acid cleaners but a small dose and short interval won't hurt anything.. hasn't killed my dad's 91 anyways. Even before replacing the thermostat the heater worked better after running it for a few days.

[rcottle]

A couple of thoughts - If the thermostat wasn't opening - wouldn't you think the car would overheat?. If nothing on the engine is getting hot wouldn't you think the thermostat was opening to soon?. I drive my festiva 7 miles to work with several stop lights. On days when it is in the 30's or below, it is usually a pretty cold ride. Last year I totally blocked of the radiator, the space beside the radiator, and put an splash shield under the entire engine - that helped a bit. I could still make the drive to work, open the hood and lay my hand on the engine. Even left everything covered up well into spring and the car never overheated or got real hot. So I have been wondering about this problem has well, because I purchased an 1988 festiva new in 1988 and I only had a heat problem one time on a trip in the winter when the t-stat stuck open - engine/heater got cold instantly...what a cold trip.
My other thought is what kind of exhaust do those of us having heating problems have? My exhaust (which was this way when I got the car) is a straight pipe from header to a cherry bomb looking thing then straight out the back (sounds good some days but is usually deafening - can't stand it) - anyway I am wondering if my lack of heat may have something to do with a lack of backpressure in the exhaust?!.. I can't imagine that there wouldn't ba a hot spot somewhere on the engine causing problems if there was a flow issue. Ok sorry to be so long winded, just my 2 cents and maybe today at lunch I will warm the car up and check for hot spots with an infared temp gun.

[m715]

Rob, the exhaust is not an issue, I believe. The car I wrote about had stock replacement exhaust with correct cat, resonator, and direct fit muffler. Curmudgeon has had a hollowed cat, 2 1/2 pipe, and stainless OEM resonator off a truck for years now,and has GREAT heat in all temps. Wish that were the solution.
Seems the B3 is WAY understressed. The only times I have seen overheating issues in any I have seen has been with a radiator tank, belt, or hose failure where NO coolant or flow was available. I have seen people use the tricks you used here, and had no overheat issues EVER. Most I have ever seen temp wise myself is 90+ degree weather, stopped in traffic, running the air full blast, and then never getting to boiling. I just don't think they run hot very easily..... maybe to a fault at times, but what happens when no heat is available still evades me. Maybe someone will figure out this mystery as how the coolant can still circulate to the intake, but not heat up. I have to wonder if this doesn't also contribute to poor performance/gas milage drop off in cold conditions too due to an incorrect sensor reading of the engines true operating temp.

WHEW!!! Sorry......

Michael

[TominMO]

I'd suggest replacing the thermostat with a new dealer one. Thay way you can narrow down the cause of the problem; and quite possibly it IS the thermostat.

[Mike McKown]

A couple of thoughts - If the thermostat wasn't opening - wouldn't you think the car would overheat?. If nothing on the engine is getting hot wouldn't you think the thermostat was opening to soon?.

Ok sorry to be so long winded, just my 2 cents and maybe today at lunch I will warm the car up and check for hot spots with an infared temp gun.

If you look at the flow diagram that was posted above, you can see the coolant can bypass the thermostat completely via two different routes, circulate coolant around it and return it to the pump to start the cylcle all over again.

I have no explanation why I can't feel hot spots on the engine with my hand unless the engine is just not heating up. I do know that back in the summer, the engine cooling fan came on a few times. It's supposed to come on at 221*F but now, it doesn't come anyways close to that operating temperature.



I think I'll go buy an infra-red gun after while. I see they are on sale at Home Depot for around $45.

[m715]

Yes, it can circulate as the training diagram shows. Why the engine can stay so cool to the touch is a real mystery when you would think the head and V/C being aluminum could feel at least very warm while running for any period of time. Maybe Jim could shed some light on this if he is watching. I do know that this time of year, my cars that have heat only move slightly off the first mark on the guage, and all are equiped with dual stage factory thermostats.(they DO make a difference) This is while it produces enough heat that once the car is warm, I have to dial back the temperature selector so as not to break a sweat. Keep in mind that I have a 1 hr commute, and with a 24 deg morning today, it took close to a half hour to get the poorly insulated car to that point.(no carpet, holes rusted in floor)

Michael

[Mike McKown]

Just FWIW.............

1988 Engine, Emmisions and Related Systems.

Sez here:

A two stage thermostat is used for better coolant temperature control with less fluctuation and quicker warm-up. It operates in this manner:

* Stage 1 - During cold weather operation 188* to 193*F only the sub valve opens to control engine coolant termperature.

* During normal operation above 193*F the main valve opens to permit increased coolant flow through the radiator.

This would suggest that in cold weather operation, the main valve in the thermostat may NEVER open and that would be/could be considered normal. All the coolant would flow thorugh the heater by-pass circuit, the thermostat by-pass hose and the sub-valve on the main thermostat.

I wouldn't argue the point because I don't know but it appears a single stage aftermarket thermostat would make the engine heat up but just would have as much finite control over an even engine temperature as the two stage factory unit.

[hot4dl8ly]

Hey Eric, what in the world is MMO, and where can I get it? Also rockauto has the correct two stage motorcraft t-stat, more expensive than the others but in my opinion-worth it.

[ericsmith32]

Mystery Marvel Oil.. red bottle at Wal-mart. Good cleaner and lube for about everything. BTW on the thermostat Amazon is cheaper if you order enough to qualify for free shipping. I got the thermostat and gates timing belt with tensioner for $66.

[grey]

As i understand it, the radiator is being bypassed completly (?), and the heater is not getting hot water for some reason.

I would remove the thermostat and run it a little. Not because that is a good idea, but just to see what happens...

pull the heater hoses one at a time and check flow.
compare in out temps of heater hoses.

[Mike McKown]

Thought I'd post an update here since there seems to be many Festiva "no heat" problems.

First off, the engine wasn't getting hot or hot enough. In spite of the fact that I dunked my factory thermostat in a pan of hot water and observed it apparently functioning like it should, the thermostat didn't work in the engine, real world.

So instead of taking a chance that a new factory thermostat might be a waste of money, I bought a new NAPA 195* thermostat. Long story short, that got the engine hot. Now, you cannot touch the engine or the hot water piping after the engine has been running a few minutes. So, one part of the equation is solved.

Now, my heater floor duct blows pretty warm air (it could be warmer) on the passenger side, cold air on the left. It even blows a little out of the left defroster duct with the control set for "floor". Before is was luke warm on the passenger side and cold on the driver's side. Again, long story short, some junior mechanic has had the dash out of this car and it appears that he has lost some parts to the ducting doors as some of them are non-functional. I think this car used to be an AC car and somebody removed the AC. How much or little of it, I'm not sure. Anyway, it's a mess and looks like I will wind up pulling the dashboard out of the car to fix it. In the meantime, I duct taped shut the opening in the duct that was blowing cold air.

Now, if I still have one mystery. The fan motor resistor. I can't find it. The blower motor runs on high speed only. Anybody know where it is located?

I'll say one thing about the NAPA 195* thermostat. It works BUT, it seems to make the engine cooling fan cylce off/on quite a lot compared to another one of my cars that has a factory thermostat. It also takes longer to get the temperature up in the cooling system than the factory stat.

I guess Mazda/Ford knew what they were doing when they designed the high dollar OEM thermostat. I'm going to buy the OEM and replace the NAPA part.

Thanks for everyone's suggestions.

[Pu241]

Glad you seemed to have solved most of the issues.