STILL overheating bad

[Camelwagon]

Ya I think too that the temp would be quite a bit different from the coolant than the actual engine block so I dont think I wanna go that route. I could probably connect the wires in from the old sending unit to a new gauge.

See personally I dont think its the rad. I used to have a 90 Mazda MX6 and it had the same problem, the gauge showed hot most of the time. I took it to Mazda dealer, they cleaned the rad, did all kindsa stuff and tests and they couldnt come up with anything. I replaced the gauge, sending unit.... nothing. They were baffled, they tested the coolant and it wasnt as hot as the gauge said it was so they thought it was some wiring thing and I didnt want to spend money for that. So same for this I think, like I said, the rad cap isnt even hot when I touch it, no boiling into the overflow tank, no hot smell in the engine... and I dont really wanna spend much money on it. But I may call around rad shops to get quotes.

[Camelwagon]

How do you clean it yourself?

[MorganM]

Go buy a cheap mechanical temp guage and see if it's really over heating or not.

 

If it really is I'd buy a new radiator.

 

If it isn't I'd properly mount that new guage in the cabin and drive it like I stole it.

[KStretch55]

How do you clean it yourself?

 

Pull the radiator out. Seems like there is a strap across the center vertically that has to come off in order to remove the top and bottom plates. Then you carefully uncrimp the clamps that hold the left and right tanks in place. The clamps kind of resemble a zipper. Once you do that, carefully remove the end tanks. They have a rubber gasket/o-ring recessed in a groove on them, don't damage the gasket. Now you've got the ends of the tubes exposed and you'll probably find a lot of gunk blocking most of them, especially toward the bottom. Use a soft bristle brush to remove as much as possible with some soap and water. Do the same to the inside of the end tanks. Make sure you get the gasket groove and seating surface as clean as possible.

Then take a stiff wire or .040" mechanics/safety wire or (someone told me about this after I'd done mine) a piece of sheet metal 36"L x 3/16"W x .040"T and work it through the passages. If you use the wire, be patient, you have to hold it with a pair of pliers and work it through a little bit at a time. Sometimes you have to use a light tapping motion to break through some of the deposits. I think the piece of sheet metal would be much easier and work better. Use a garden hose held against one end to see which passages are restricted or blocked. Keep working until they all flow freely.

Then, dry everything off good and apply a thin coating of RTV to the tank gaskets. I do this by putting a dab of RTV on my thumb and index finger then sliding the gasket between them. You don't want it globbed on, just evenly coated. Put the gasket in the groove and carefully reassemble and recrimp the clamp carefully. Try to use even pressure all the way around. Reassemble the other tank the same way. Let cure for 24 hours. After 24 hours (if you can't wait that long, I'd go at least 12 hours), refill the system with coolant and leak check (unless you have a coolant system pressure checker, then of course check it before you fill it). If you don't see any leaks, let it get up to operating temp then let it cool and check your fill level, add as needed. Burp the system to get any air out. I usually put my front wheels up on ramps to aid the burping. If you don't have any leaks, you're in business and it just cost you some time. Good luck!

[Camelwagon]

A friend of mine said it could also be my water pump not working and thats causing overheating.?.?

 

So whats the difference between a mechanical temp gauge and the one in the car? How and where can I hook up the mechanical gauge? Does it not need to be hooked up with wiring?

Thanks.

[zyewdall]

So whats the difference between a mechanical temp gauge and the one in the car? How and where can I hook up the mechanical gauge? Does it not need to be hooked up with wiring?

Thanks.

 

Nope. It's got some sort of capilary tube with alcohol in it that goes between the sensor and the dial guage. I think you have to find that adaptor to go from whatever screw threads the sensor has, to the screw threads in the thermostat housing where the electric temp guage sensor is. Problem is it's probably metric on one side and english on the other... PITA.

 

I haven't read the whole thread here, but have you tried running it without the thermostat? If the radiators not hot at all and the engine is, that's the first thing I would suspect.

[zyewdall]

A friend of mine said it could also be my water pump not working and thats causing overheating.?.?

 

Could be. A friend of mine had an old MG miget that always overheated, and after replacing radiator, thermostat, flushing block, etc, it turned out the water pump impeller was corroded away.

[Camelwagon]

Hm I might have to try a gauge like that then. Ya I already replaced the thermostat though with no change. Thanks.

[zyewdall]

Hm I might have to try a gauge like that then. Ya I already replaced the thermostat though with no change. Thanks.

 

One more thing on the thermostat -- we just had a '90 legacy that kept overheating, and some guy at the parts store said you have to exercise the new thermostats -- push them open and closed for about a minute to loosen the spring or something -- before installing them. Sounded wacky to me, but we tried it, and the car doesn't over heat now.... But we also did a full cooling system flush, so who knows.

[nipper]

Ok oddball things to make a car overheat...especially on cars with high mileage

 

1- The impeller in the water pump seperates from the shaft. This is rare, but not unheard of in high mileaage cars.

 

2- The impeller can erode. Ideally one would want to use deminierilzed water and Subaru antifreeze, especially since middle age of subarus seem to be around the 180K mark. On other cars its rare they are still functioning at the 120K mark with an eye to making it farther then that.

 

Either 1 or 2 may have a leak out of the weep hole in the waterpump, but not always.

 

Exercising a thermostat is the silliest thing i ever heard. And really the true way to do that is by put it in boiling water, which is a test that should be done anwya when you have an odd overheat issue. Put the thermostate in a pot of water with w meat thermometer, and see when it opens up, and if it fully opens up. Another cause can be a thermostate installed backwards. ALso check for weak, colllapsed raditor hoses.

 

 

 

nipper

[zyewdall]

Exercising a thermostat is the silliest thing i ever heard.

 

That's what I thought too.... And the update on the '90 Legacy is that it still overheats. We thought maybe it was fixed, but no dice..... I'm going to take a look at it again tonight.

[nipper]

Lets get everything down on one page:

Combustion gasses in the radiator?

Cooling fans working at full speed?

Radiator Clean?

Cooling fins in good shape and attached to the radiator

Radiator cap good?

Radiator hoses good?

Are there any collapsed Hoses?

Does the car get heat?

Has the engine block been burped?

Are all the cooling fans in one peice?

Has the system been backflushed?

Is the AC condencer clean?

Can you see water flow in the radiator once the thermostate is open?

Run the car without a thermostat and check for flow.

Check the coolant temp sensor for function.

 

After all that, i would start looking at the waterpump.

 

nipper

[Camelwagon]

Ya I flushed and backflushed the rad, fan is good, 2nd fan doesnt seem to come on though when it overheats. No heat in the cabin when I turn the heat on full blast. But the heater core hoses are really hot.

What do you mean by collapsed hoses, how do they look?

[MorganM]

it literaly collapses; no longer round but flat.

 

the electric fan doesnt come on? I'd get that fixed.

 

did you get that guage on yet?

[zyewdall]

Lets get everything down on one page:

Combustion gasses in the radiator?

Cooling fans working at full speed?

Radiator Clean?

Cooling fins in good shape and attached to the radiator

Radiator cap good?

Radiator hoses good?

Are there any collapsed Hoses?

Does the car get heat?

Has the engine block been burped?

Are all the cooling fans in one peice?

Has the system been backflushed?

Is the AC condencer clean?

Can you see water flow in the radiator once the thermostate is open?

Run the car without a thermostat and check for flow.

Check the coolant temp sensor for function.

 

After all that, i would start looking at the waterpump.

 

nipper

 

Good list. How do you burp an engine block?

 

Someone told me last night that there could be an air bubble in the engine block that is keeping the coolant from circulating. He said you have to fill the block separately from the radiator? It could explain the heat not working in the cabin as well.

[Camelwagon]

Ya I burped it all, I dont think thats it. I've flushed and cleaned so many other radiators and no bubbles have ever come up. And if there was a bubble, it couldnt be so big as not to get any heat at all in the cabin, at least it would come in spurts here and there.

I'll check the hoses. The main fan works but just not the 2nd. I'll get the gauge soon. Thanks.

[nipper]

Oh yes it could. this is something you want to always check. Its amazing what air traaped in a cooling system can do..

 

 

nipper

[Camelwagon]

Well I've flushed it twice, burped it a couple times... nothing.

So how many coolant hoses are there, the 2 rad ones, 2 heater core... wat else? I know there are some smaller ones...

[nipper]

Are the rad hoses soft? are they dry rotted? i dont remeber if there are any tiny bypass hoses on this thing or not, somne ask can answer that.

 

 

nipper

[Soob Flyer]

Here is something that is very unusual about the subaru engine. The cold water comes in to the engine past the thermostat which is exactly the opposite to any other vehicle out there. Now before anybody yells B.S. and says how can the thermostat open in cold water, what you have to take a close look at is your heater curcuit. You will notice the return from the heater core is piped in to where it hits the thermostat squarely on its element which makes it open and let cold water into the engine while mixing it with the hot from the heater so as not to shock the engine. You may have noticed that port there where it comes in when you changed the thermostat.

 

So your real problem here is your heater core is plugged and is not letting enough flow go through to hit and open your thermostat. That is why it has already been suggested to try a by pass loop on your heater to confirm that it will cure the overheating problem. I can see a new heater core in your future!

[KStretch55]

I have to disagree, in part. The "pill" on the thermostat sits in the block side of the housing because it's intent is to sense when the coolant in the block has heated to normal operating temp and then it opens to allow flow through the radiator, all the while opening or closing as needed to regulate the coolant in a given temperature range. You are correct in that the heater return hose does pipe warm water to the thermostat housing, but as I recall that is because the heater core and associated piping is the primary, if not only, bypass system on these engines. The bypass system allows for a reduced coolant flow during engine warm up. Otherwise, the engine would produce hot and cold spots in the block and because heat rises, even in liquid, the thermostat would open too early before the lower part of the block was warmed up. Once the engine begins to reach operating temp the thermostat begins to open and allows hot coolant to pass through to the top radiator hose, the coolant then flows through the radiator and is picked up by the lower radiator hose and taken to the pump, then pumped back into the block. On a properly operating system you can prove this by feeling the upper hose while the engine warms up. The hose will be flexible (not pressurized) and not be hot until the theromstat opens, then it will be tight and hot, while the lower hose will be noticeably cooler to the touch.

 

I still say camelwagon has a very plugged up cooling system. If he's getting some heat from the heater I'm betting that's the only heat transfer that he's got going on, cuz' sounds like the radiator is almost, if not completely blocked.

[azsubaru]

So how many coolant hoses are there, the 2 rad ones, 2 heater core... wat else? I know there are some smaller ones...

 

Don't think this would cause your problem, but, let's see, there is a little short tiny one just behind the throttle body, and another one just to the driver's side of the thermostat housing, don't remember any others at the moment.

[Camelwagon]

Hm Soob Flyer made sense a bit but both of the heater core hoses are really hot (even tho theres not much heat in the cabin), so that means coolant is going in and out of the core. And when I flushed the core a couple weeks ago, i put the garden hose to both holes and water gushed out freely from the opposite hole. Same with the radiator. But then again they both could be partially clogged up. So I just dont knoooooow, I'm going nuts here. Oh well its not my daily driver so i'll see what happens. I'll try the gauge thing though fo sure. Thanks guys.

[nipper]

Have you replaced the radiator yet?

 

 

nipper

[zyewdall]

I have to disagree, in part. The "pill" on the thermostat sits in the block side of the housing because it's intent is to sense when the coolant in the block has heated to normal operating temp and then it opens to allow flow through the radiator, all the while opening or closing as needed to regulate the coolant in a given temperature range. You are correct in that the heater return hose does pipe warm water to the thermostat housing, but as I recall that is because the heater core and associated piping is the primary, if not only, bypass system on these engines. The bypass system allows for a reduced coolant flow during engine warm up. Otherwise, the engine would produce hot and cold spots in the block and because heat rises, even in liquid, the thermostat would open too early before the lower part of the block was warmed up. Once the engine begins to reach operating temp the thermostat begins to open and allows hot coolant to pass through to the top radiator hose, the coolant then flows through the radiator and is picked up by the lower radiator hose and taken to the pump, then pumped back into the block. On a properly operating system you can prove this by feeling the upper hose while the engine warms up. The hose will be flexible (not pressurized) and not be hot until the theromstat opens, then it will be tight and hot, while the lower hose will be noticeably cooler to the touch.

 

I still say camelwagon has a very plugged up cooling system. If he's getting some heat from the heater I'm betting that's the only heat transfer that he's got going on, cuz' sounds like the radiator is almost, if not completely blocked.

 

The thermostat in the legacy is on the bottom hose instead of the top hose going to the radiator. Does the entire coolant system flow the opposite way on it, or does the EJ22 have the thermostat on the cold side perhaps? Sure would be helpful if the hoses had flow direction arrows on them like most HVAC systems do.