Heater as a heat pump?

[CzarMohab]

5 pictures were taken in chronological order, and within 20-30 seconds start to finish. I can't seem to get them to upload to this post, but they are in my photo's section.

 

1st is Temp gage at almost red mark,

2nd is showing heater is on full blast,

3rd shows outside temp,

4th shows temp gage alot cooler

5th shows heater off.

 

Basically, I didn't think that anyone would believe me if I said that the heater being on makes the engine hot... and turning it off makes it cooler... Not the AC or fan on cool, just the heat being on hot.

 

I know that the radiator is more or less a goner, and I am in the process of procuring a new one.

 

But seriously, I have to ask, what strange new disease is plaguing this car? I turned the heat on to help cool it down going over some long, tall hills, and didn't turn it off because it never got cooler again. I decided that it was too bloody hot to have it on and as soon as i turned it of, the car went cold. had to do it all over again so I could get the pics, but other than that, heats staying off for a while

[nipper]

Check your altenator output. It can sometimes give you a false high temp gauge reading if the output is too low.

 

nipper

[DaveT]

I'd say it's coincedence. - Adding - I haven't seen the above electric problem. I have had alternators fail, but never noticed that.

 

>>> IF you don't have electric system troubles, read on. <<<

 

I've overheated a few. It is normal for the temp to go way up, then suddenly down. When the cooling system is not 100% full of coolant. If the system isn't full, and at pressure, coolant can boil. It doesn't cool very well that way... Water pumps aren't good at pumping steam or air.

 

The heater core is just fed coolant in a path that bypasses the thermostat. Heat on / off only move doors that effect airflow through the core.

 

Other things that likely need replacemnet:

Thermostat.

6 coolant hoses, if it has really been cooked.

Water pump.

Radiator cap.

Valve seals.

Headgaskets. If not now, they will begin to show signs of failure sooner than later.

 

Get it hot enough, and you need rings too.

 

The above is what to do to repair the damage from overheat. What caused it originally, at this point, is hard to say, not enough pre-overheat details.

[CzarMohab]

I honestly think that with as many issues as my car has had in the last 7 months, I should just post a summary of everything that has happened so everyone is up to speed.

 

Nipper:

 

New alternator. No issues noted after installation tests were run, and courtesy check after water pump replacement work was done revealed nothing abnormal, but I will have someone look at it when I get the chance. Hopefully, this is all it is.

 

Dave, et al:

 

Pre-overheat: Water pump pulley, fan, and water wanted to go play on the highway. One of the studs holding it all together sheared (in the water pump drive end) and the other 3 were wanting to. This destroyed the water pump (hence the water on the highway) and cost me over $500 to repair (*&^% schucks and their sales, NEVER AGAIN from them will I buy anything that could cause such damage; but at least I got my money back for the defective pump). Overheat (red zone) time was minimal. When the fan & pulley went, they tried to take the radiator with them hence the warmer car (alot of fins were bent, I spent well over an hour unbending what I could). Car was fixed almost one week ago.

 

Post-repair/overheat: It only climbed into the red zone going over those bloody hills heading into Yakima. Ironically, almost the same spot where all the BS started. Turned heater on to help dissapate the heat (heat sink = heat out so in theory, and as i9t had before, it should work) and after cresting the hill at a measly 20mph, not in the red zone, I left the heater on. Finished the other 2-5 hills (depends on how you call them hills) at 60mph no issues just REALLY warm. Then traveled about 45 miles with the heat on and no real change in engine temp, just not as warm, when I was getting too hot so I turned off the heater. Temp went down. Alot. Got to speed up to the speed limit of 70, too.

 

I understand the physics behind it. I understand the heat transfer stuff behind it. Theories and texts and equations... yeah, I got the idea. Seen some strange stuff in my day (ex navy nuclear operator), but this takes the cake. If Nipps is right, then its no big issue, but if it is something else, then someone please explain to me how in the world a heat sink is adding heat to the engine?

[Ross]

IF you really are sure that opening the heater valve causes the engine to overheat (I presume that is what you mean...), then i'd say the only things that could be behind it are blocked coolant passages and/or hoses, or a problem with the water pump or perhaps thermostat. Opening the heater valve will change the flow characteristics all over the place, which may lead to a lack of water being pumped through the main radiator. I'm guessing that you are talking about an ea82 - i'm not familiar with the exact layout of their cooling system. Looking at a schematic of the layout would most likely be a good place to start.

[daeron]

poor gauge grounding can also apparently cause the voltage dependent "temp spike" on the gauge... but this is "internet parroting" and not something I have experienced.

 

Low water level can cause pump cavitation when you turn the heater on; I experienced this alot... i had a bad headgasket blowing cylinder compression into my radiator, it ran okay and wasnt contaminating anything so i drove like that for about six months before i could do the HGs..

 

Also, there is a possibility that a clogged heater core might cause an issue along these lines... I would call it more of an outside possibility, but it is easy enough to disconnect both hoses, hook a garden hose up to one end, and blast it out (carefully, of course.. pressure can kill..)

 

HTH

[nipper]

First thing is first, replace the radiator. SInce you know its dead, do that and i bet the problem will go away.

 

 

nipper

[thealleyboy]

I would temporarily disable the HC, until your questions have all been answered satisfactorally. Just bypass the core so that the flow goes from the engine outlet to the return inlet.

 

With the heater core no longer in the picture, you can assess the "overheating" issue on it's own merits. I would try to nail this down before the new rad if at all possible. Sure it's never a bad idea to replace an old, but there could be multiple issues here. You could end up burning up your motor anyway, and the radiator will end up being a waste of $$.

 

good luck, John

[Gloyale]

IF you really are sure that opening the heater valve causes the engine to overheat (I presume that is what you mean...), then i'd say the only things that could be behind it are blocked coolant passages and/or hoses, or a problem with the water pump or perhaps thermostat. Opening the heater valve will change the flow characteristics all over the place, which may lead to a lack of water being pumped through the main radiator. QUOTE]

 

There is no valve in the EA82s, the heater core has circulation through it always. Changing settings on the dash only affects how air is directed, there is no change in coolant flow through the system.

[daeron]

 

There is no valve in the EA82s, the heater core has circulation through it always. Changing settings on the dash only affects how air is directed, there is no change in coolant flow through the system.

 

 

Is the heater core an integral aspect of the flow of coolant? or is it a parallel flow circuit to other means of coolant circulation? in other words, does ALL the coolant always flow thru the HC?

 

I didn't think so, but i was in a discussion with someone and they tried to tell me i was wrong, and i had no real knowledge to back it up; just my impression that it was a parallel circuit.

[CzarMohab]

From looking at the hoses, I think this is how it goes:

 

Water pump -> Engine block -> T-stat -> Top rad hose -> Rad -> Bottom rad hose -> Water pump

 

Water pump -> Engine block -> Hot heater hose -> HC -> Cold heater hose -> Water pump

 

Like I said, I *think* this is how it goes.

 

Only things I can imagine it being are 1.) what nipps said, electrical issues or 2.) its so dang hot out that its putting heat into the coolant. It was so hot today that I didn't even need to wait for the car to warm up, it already registered temp on the temp meter/gage thingie. 110F on the digidash thermometer.

 

So on a different note, yet the same... where should the temp gage hang out normally? Mine seems to have taken residence at 50% lately (all the "hot times" not included). Seen it hold both colder and hotter over the last few months. Need to know so when I get new rad in i know its working right.

[Skip]

At the time these cars were manufacted(sic)

 

there was a TSB* about this on the cars with

the digiacrash(sic) dashes describing this problem.

(*Technical Service Bulletin)

 

I had an 87 GL-10 that would do this.

 

The ground for the dash el. components wanted cleaned and tightened.

 

You will find this ground under the passenger side front

intake manifold bolt.

 

Gloyal said it best - there is no valve on the heater core

just a "blend door" to adjust the heat into the cabin.

You no doubt turned the fan on thinking it would help.

 

The other loss of voltage to the dash comes from the fuse box under the dash.

The power wire coming from the fusible links to the main feed on the back of the fuse box has trouble.

 

DO AS Nipper says - get the NEW rad - not some hooky flush/backyard "think it's good"--> unless you like pulling engine and doing head gaskets???

 

If this still bothers you get a real gauge installed.

 

Hope this helps.