1994 Camry: Overheating

[Miramonti]

I replaced the thermostat, but it's still overheating. Fwiw, the old thermostat was still good too.

Water however is not circulating thru the radiator at all, and I'm thinking the radiator might be clogged because a water pump probably wouldn't completely go out like that, right? I always hear about water pump bearings going out and making noise etc. but everything sounds fine when running.

What's the best way to approach this, maybe disconnect the radiator and send water thru it to see if its clogged? Could it be something else?

 

[skyking]

Don't know about a 94 but I just did my 98 water pump last weekend. IF, and it is a big if, you have a plastic impeller it can separate from the shaft and you have no water pump.

 

[Vette73]

I've actually seen a water pump wear out the implers and not move enough water. That of course is very rare, at least in my exp.

V6 or 4cyl?
But I think the timing belt runs the WP. Easy way to test is remove the Therm and run car with hose off. See if water if flowing. If it is hook hose up and see if it flows through the Rad.

 

[T2urtle]

plastic impellers do break off easily... mk4 jetta/gti/golf/passats do it all the time. wheel just breaks or cracks off

feel the upper and lower radiator hoses, ideally they should be the same temp. if not then it would be the flow since you replaced the t-stat.

 

[bruceb]

Start with the water pump. It is old and the impeller does wear out over time and as mentioned, it may not be turning internally. Also, flush the entire cooling system and refill with a 50/50 mix antifreeze / distilled water. Put a new pressure cap on it. And check to see if your electric cooling fans are running when they should be. They should kick in around 200° - 210° F or so or when the air conditioner is turned on.

 

[exdeath]

The OEM Aisin water pumps used on those model Toyotas do not use plastic impellers and don't wear out that way. They just make noise, develop play, and leak coolant.

You won't feel anything in the hoses at all until it's at operating temp when the thermostat opens and the fan comes on, so you have to let it sit running for a while.

To check radiator, let it run full temp for a few minutes with the fan disconnected and removed, and feel around for uniform temperture/cold spots on the radiator.

Hoses should not have pressure if coolant is circulating (high velocity = low pressure), you should be able to squeeze them rather easily and feel the fluid rushing through them once the thermostat opens.

When you first turn it on cold, both upper and lower hoses will have pressure because the return from the radiator is blocked by the closed thermostat. When the thermostate is open, there should be no pressure in either hose. If you have pressure in the upper hose and no pressure in the lower hose, the radiator is causing a restriction.

PS: sorry for excessive edits, I had my cooling systems/cars mixed up.

 

[Miramonti]

Thanks for all the replies, guys, they are very appreciated.

This is a 4 cylinder.

I had no idea the impeller could be plastic!

After warming up the car, water actually boils in the upper radiator hose but there is little pressure/heat in the lower hose going from the radiator to the thermostat. (I'm fortunate the hose didn't burst to this point.) This is why I thought it might be clogged, before learning the water pump can break.

Which direction does the water flo thru the radiator? I'm thinking out the block, into the upper radiator hose, out the lower hose and thru the thermostat/into block?

Don't know about a 94 but I just did my 98 water pump last weekend. IF, and it is a big if, you have a plastic impeller it can separate from the shaft and you have no water pump.

I'm curious, in case this is what's needed, was the pump easy to get to and replace? Any tips? It would be nice if it were as easy as replacing the thermostat for this car.

 

[Miramonti]

Start with the water pump. It is old and the impeller does wear out over time and as mentioned, it may not be turning internally. Also, flush the entire cooling system and refill with a 50/50 mix antifreeze / distilled water. Put a new pressure cap on it. And check to see if your electric cooling fans are running when they should be. They should kick in around 200° - 210° F or so or when the air conditioner is turned on.

I've replaced the cap already as well. The relief valve? broke when taking it off, and I figured that would be a good thing to work properly at this point.

As for distilled water...hmmm, this is a beater. As soon as I can get it to sellable condition, I'll probably be letting it go.

 

[Miramonti]

Btw, do places that accept used oil, like walmart, also accept used radiator fluid?

 

[exdeath]

Thanks for all the replies, guys, they are very appreciated.

This is a 4 cylinder.

I had no idea the impeller could be plastic!

After warming up the car, water actually boils in the upper radiator hose but there is little pressure/heat in the lower hose going from the radiator to the thermostat. (I'm fortunate the hose didn't burst to this point.) This is why I thought it might be clogged, before learning the water pump can break.

Which direction does the water flo thru the radiator? I'm thinking out the block, into the upper radiator hose, out the lower hose and thru the thermostat/into block?

I'm curious, in case this is what's needed, was the pump easy to get to and replace? Any tips? It would be nice if it were as easy as replacing the thermostat for this car.

Exits the block at the driver side rear of engine to the upper hose through the radiator and enters the pump/thermostat housing from the lower hose at the passenger side front of engine.

Quick test, pull the upper hose off the radiator and start the car when it's cold (just for a few seconds). Coolant will flow immediately if the pump is working. You can do the same thing with the lower hose to check flow from the radiator. Both of these are before the thermostat and should flow profusely even when cold, at the same rate, under purely pump pressure.

The upper hose, radiator, and lower hose is a serial circuit. Pressure across the whole run should be the same. When cold, both upper and lower hose should have pressure because it's all blocked at the thermostat. When hot, niether should have pressure, because it's freely flowing with an open thermostat. If the thermostat is closed, both hoses will have pressure. If there is severe pressure at the upper and absolutely none on the lower, hot or cold, time for a new radiator.

 

[exdeath]

http://www.turboninjas.com/camry/eg1.pdf

More than you ever wanted to know about the 2.2L 5SFE. Page EG1–238 for cooling.

turboninjas lol? Was looking for toyotanation or something, but as long as the file is there that's all that matters.

 

[Miramonti]

http://www.turboninjas.com/camry/eg1.pdf

More than you ever wanted to know about the 2.2L 5SFE. Page EG1–238 for cooling.

turboninjas lol? Was looking for toyotanation or something, but as long as the file is there that's all that matters.

The whole manual?? That should be helpful, thanks. :thumbsup:

Holy crap, it says to remove the timing belt to replace the water pump! This is pretty involved. I'd probably want to have a replacement timing belt ready too (if I choose to undertake this), just in case it's ready to replace.


For starters, I'll disconnect the radiator hose and to check for water pressure and see what that leads to. I'm not afraid of the job as I am of the time inconvenience and not having all the necessary tools. Fortunately I'm near a harbor freight.

 

[exdeath]

Yes, most imports have the water pump behind the timing cover driven by the timing belt. If you're at 100k plus you'll want to do everything while you're under there; oil pump formed o ring, cam seals, oil pump seal, front main seal, etc. They are very easy to do and the extra bits don't add more than $50 to the parts total, it's getting to it that is the pain in the ass. But it's not essential, as you have to be in there every 60k miles for a timing belt and water pump anyway.

Getting the front bracket that crosses the timing cover and comes up for the little dog bone mount is probably the worst part. 6" bolts with 2" of clearance between the engine and fender

 

[Miramonti]

Yes, most imports have the water pump behind the timing cover driven by the timing belt. If you're at 100k plus you'll want to do everything while you're under there; oil pump formed o ring, cam seals, oil pump seal, front main seal, etc. They are very easy to do and the extra bits don't add more than $50 to the parts total, it's getting to it that is the pain in the ass. But it's not essential, as you have to be in there every 60k miles for a timing belt and water pump anyway.

Getting the front bracket that crosses the timing cover and comes up for the little dog bone mount is probably the worst part.

I'm definitely going to need more information about these if I wind up needing to do this 'project', including what "etc." means.

There are some definitely oil leaks, atleast one noticeable one somewhere, and maybe this is a blessing in disguise.

 

[skyking]

The OEM Aisin water pumps used on those model Toyotas do not use plastic impellers and don't wear out that way. They just make noise, develop play, and leak coolant.
<snip>

No noise, but definitely play and a very stealthy leak in my case. It did not run down, it turned to steam and it was dependent on RPM. at idle it did not show itself, the bastige! I got home friday night and the temp gauge went to the peg.

I'm curious, in case this is what's needed, was the pump easy to get to and replace? Any tips? It would be nice if it were as easy as replacing the thermostat for this car.

No it is a pain mostly due to the proximity of the unibody. I also had the pleasure of stripping out the head of the only phillips head screw that retained the pump, and had to pull that thermostat and pump housing out as well. I suggest pulling that housing to start with, since it is nearly impossible to loosen that screw without an impact driver anyway. The 98 had a 90,000 mile service interval on the belt but I think older ones like yours are less.
I lost the first belt because I "forgot" to change it in a timely manner
at 120K I was driving along and heard this curious thump and things got quiet
It is a non-interference engine, no harm no foul.