Overheating problem, help please...

[svxcuseme]

I don’t have any of that. I flushed the radiator, putting tap water where the hose connects to the top. While some dirt water was coming out initially, good amount was coming out, not drizzling.
On the other hand, I’m having overheating pretty immediately even under idling. So I also feel that it’s the water pump or clog somewhere in the system ( but may be not radiator due to above.)

One question, bottom of my radiator is warm / cool. I guess the thermostat never got hot on that side. Would the water in the water pump side get hot enough to fail the thermostat?

Yes, if the car is overheating the thermostat could fail. The Thermostat side that gets hot is on the engine side. The heat sensitive pellet and spring face the engine, not the radiator, so the coolant coming from the radiator does not play a significant role in opening the thermostat.

Coolant flows from top to bottom in most radiators. Your symptoms, definately point to either bad pump or radiator. Wish you were closer so we could swap in a good radiator and test that first.

Water flowing through the radiator is good but sediment could still have built up in the passages, enough the invalidate the radiators cooling capacity. A good way to see how much sediment is in the radiator is to remove it completly. Attach a garden hose to the lower radiator outlet with some duct tape. Turn on the water and spank the radiator around the aluminum body, not the plastic tank (be careful not to flaten the aluminum fins). This should produce enough vibration to allow some sediment to backflow and give you a good idea if there is significant sediment build up.

To determine if the water pump and engine water passeges are working, fill the system, disconnect the top radiator hose, remove the thermostat, introduce some water source (garden hose or better yet a gallon of water with a hose duct taped to the lower hose) and start the car (when it's bone cold). Does coolant spews out the top hose? This would give you a good idea as to whether your water pump is actually pumping.

You would have to remove the thermostat for this test, otherwise no coolant would be free to flow past it when cold. You would also need to orient the gallon of water above the lower hose to allow gravity to excert some pressure and keep coolant from back flowing through the lower hose. You should also poke a hole in the top of the gallon jug, opposite the hose to keep from creating a vacuum that the water pump would have to pull against. Does that make sense?

Or you could purchase a radiator from one of the big chains (make sure they have a money back return policy), install it and see if your problem goes away. If not, return the radiator and your not out anything but some time.

Are you refilling the radiator or resevoir frequently? Do you have fumes from the exhaust, white smoke from the tailpipe that dissipates in the atmosphere quickly? IS your oil, milky looking (water and oil mix).

Since you don't have any of this and no mentioned performance degradation, I'm definately leaning toward a coolant flow problem as stated above. I'm doubtful you have a bad head gasket.

[redsvx94]

Thanks for the idea, svxcuseme
I actually tried it and found water is not splashing out at all from the top hose. The water was coming out of top hose to radiator (which now is disconnected), when I topped it off at the water pump side. So it seems there is no complete clog in the passage and the culprit seems to be the water pump. I will be off for the work for replacing it and other things while I'm down there.
Also I will back flush the radiator. If there is no extensive amount of sediment, I wonder how I can check whether its flow paths are good enough? Is there any spec like at what pressure how much of flow it should be? Not that I could exactly measure those but I assume I can do some rudimentary checking using tap water pressure and measuring the water coming out.

By the way Beav, you recommended to replace the harmonic damper when water pump had a problem. Can you explain why it should be changed?

[Beav]

I don't recall ever stating that.

[redsvx94]

Oops, I'm sorry. What you mentioned is the hydraulic tensioner, and I thought it was the same as harmonic damper. Could you let me know what exactly that is?

Thanks.

[Beav]

It's the cylinder that applies pressure to the timing belt tensioner pulley. Sorry, I don't have any pics available but the parts counter will.

[redsvx94]

Is that one with part number 13068 in the attached pdf?

Is this one of the items that needs to be changed along with timing belt (including front engine seals and water pump) or does a bad water pump have an ill effect on it? I'm asking, just because the how-to that is for usual Timing belt change doesn't seems to mention changing it.

Thanks!

[Beav]

Yes, #13608 is the hydraulic tensioner. Think of it as a miniature gas strut for the hood or trunk lid. It pushes against the tensioner pulley and keeps the timing belt taut. Just as those struts lose their strength over time, this tensioner does also.

[laserx]

I had a thread going here with basicly the same problem. I tired everything and was getting ready to have the head gasket done.
The day before I was to put my car in, I thought I'd try one last thing. My thinking was that if I had air pockets in my cooling system it would cause these symtoms. I did have it fushed a couple of times but still thought what the heck. So know that the air will take the course of least resistence when heated I took off my rad cap and started the car, I then stood there and watched. After a minute or so, a big burb of air, followed over the next 5 mintues by two slightly smaller burbs, then 10 minutes of smaller bubbles, just as I thought for sure that with all this air that my HG was gone the bubbles stopped, I let it run like this for another 30 minutes with no more bubbles, I topped on the rad and overflow put the cap on and have never over heated again.

[Sr240sx]

The water pump won't leak most often if it fails, it tends to want to leak when it's gasket dies.


sounds entirely like your water pump.

if you REALLY want to test your thermostat, take it out of the car, let it close, and gently set it into a bath of boiling water on the stove.

[redsvx94]

Hi All,
As many of you suspected my water pump was the problem. It was totally seized. It's a little bit scary that pump could be dead like that without having prior sign. May be I wasn't hearing it due to AC compressor. Hopefully all would be well after replacement.

By the way does anyone have a torque spec for the bolt on the water pump?

Thanks.

[Beav]

You are replacing the t-belt also, aren't you?

[redsvx94]

Yes, of course. I'm also replacing t-belt tensioner, cam and crank seal, top and bottomed radiator hose, timing belt cover seal (may be just the center bottom one) and flushing the radiator, engine coolant path...
Can't find torque spec for the water pump. It wasn't very tight when I took it off, but I wonder such thing as metal seal may require a certain torque..

[Beav]

Torque wrench? We don't a need no steenkeeng torque wrench!

The bolts can only handle so much torque, no? Doesn't matter what the gasket is made of.

[redsvx94]

Well, I'm not entirely sure about that. (at least yet ) The metal gaskets seals by deforming, so if you over torque it could crack due to excessive work hardening. At least that's my experience in working on vacuum equipments with metal gaskets. I was concerned a little bit, since this gasket is thin and thus it has a limited about deformation it can do before it cracks.
But any way if you say so, then I probably shouldn't worry. I gave about 12-13ft.lbs for that 5 bolts.

[Beav]

When I read questions about torque specs I have to remind myself that many don't work with this stuff as much as I do. Seriously, the only things that get measured by me are head bolts, rod & main caps and wheels. Oh yeah, and the lower lateral link bolt on the rear hub. I can't recall the last time I saw my inch/lb torque wrench...