'89 Corolla cooling problem when in overdrive?

Hi all, Happy Presidents' Day weekend! Hoping the gurus on this group can help me with another issue on my '89 Corolla SR5. It has 147k miles, carbureted 2AF, and 4-speed automatic with overdrive. It runs fine, gets 36mpg on the highway. It's on its original radiator and I do get the coolant flushed about every 2 years/

10k miles. The coolant level looks good and the coolant level looks right. The exterior of the radiator looks clean and looks good. The grille, which is quite small to begin with in a Corolla SR5, is unobstructed. The water pump is original from 1989. The car normally "likes" to run at 40% of max temp, which is what I notice with other cars too. When I'm on the highway at 60-70mph though, when it's between 2400-2800 rpm, the temp often creeps to about 75% of max temp, and then either the cooling fan will kick in or I'll get to a downhill area and the temp will fall. After it goes back to 40% of max temp, it may reach 75% of max temp in about 5 minutes. Between 60-70 mph, the car doesn't have a lot of power, understandably (2500 rpm in a 1.6-liter engine) but it doesn't feel like it's lugging or struggling either. On purely level ground it probably is usually at 50% of max temp. NOW, if I turn overdrive off, say at 65 mph, then the RPMs rise by 1000 and the temp immediately falls to 40% of max operating temp within 5 seconds. Likewise, if I drive at 75-80 mph, the car is at 3500-4000 RPMs and also will run at 40% of max operating temp. If I floor the car for quick acceleration, it'll also downshift, accelerate, and the engine temp drops quickly.

The thermostat and fan switch were all replaced in the past few years, and the car operates at 40% of max temp under low-strain conditions like local driving, so I don't believe either of these is faulty.

Unfortunately I didn't pay very close attention to engine temp before so can't remember how long this has been happening. I don't remember it was happening when I bought the car back in '99. It may have been this way for a year or more, I just don't know.

Questions:

  1. is it bad that the engine temp is reaching 75% of max temp if I drive between 60-70mph in overdrive? Or is this normal? I worry that the engine isn't supposed to be above 40% of max temp for too much time. Also, I worry that cooling fans aren't meant to be kicking in every 5-10 minutes, and that the fan could easily fail if it needs to do so.
  2. given that the engine temp is cooler when the engine's revving higher, I'd have to conclude this is because the water pump is spinning faster and therefore circulating more fluid when the engine's RPMs are faster. When you see this situation, where the temp's high in overdrive, does this mean: a. don't worry about it? b. get a new water pump? ($$$) c. get the radiator "power flushed"? (don't object but am always a little leery of places that want to sell "power flushes") d. get a new radiator? ($$$) e. add more coolant though the coolant level looks ok?

Please let me know what you think, John

Reply to
johnyang97
Loading thread data ...

Wow. I don't know what to tell you to do to rectify this, but I can answer that it is unusual to get up to 75% of the gauge. Usually Toyotas are rock-solid on the temp gauge. Have you replaced the thermostat, and did you use a Genuine Toyota? I noticed with my Mazda that the temp goes up to halfway before settling back, and it didn't do this before I replaced the thermostat.

Interim, try turning the heat on when it starts to creep up. The extra cooling of the heater core might level it out better.

It sounds like you've done a good job maintaining the cooling system. But you didn't say if you have replaced the water pump. If you haven't changed the timing belt at 120,000 or so, you may be due for a belt, and the water pump is another 45 minutes labor and ~$100 for an OEM pump. Also, power flushing the radiator isn't a bad thing like a tranny; it can clear a lot of gunk out of the bottom of the radiator.

Let's see how others weigh in on this one!

(Um, those are cool cars, BTW!)

Reply to
Hachiroku

On Feb 18, 7:43 am, snipped-for-privacy@yahoo.com wrote:

Off hand, it sounds like the water pump impeller blades are corroded up, or eroded away, and may nearly be gone. I don't really think it's the radiator, or T stat, because shifting to a higher rpm would not help much at all. I don't know where the pump is on that model. If it's behind the timing belt, etc, it will be a bit of a pain to get to. If it's out in the open, much easier. I'd probably yank the pump, and take a look at it. Might as well slap a new one back in to replace, cuz at that age, the bearings are probably about toast too. I guess it's slightly possible that if the radiator was semi clogged, increasing the rpms to push more water through it might lower the temp, but usually a bad radiator will run even hotter if you increase the rpms at the same road speed. I'm leaning more to a bad water pump... It's not normal, thats for sure. BTW, if the water pump is run off the timing belt, I'd also install a new timing belt, while I replaced the water pump. Doesn't make sense not to, being you have to yank the crank pully, etc to get in there. Ditto for changing a timing belt..Doesn't make sense not to change the water pump while you are in there changing a belt, being the belt runs the pump, and a locked up pump will toast the new belt. Then you get to do it all over again.. :( Course, if the pump is run off another belt, and more out in the open, then you have it fairly easy. My 89 accord is that way.. It's pump does not run off the timing belt. But the majority of older toyotas seem to run the pump off the timing belt. We had a corolla once that was your year, but I never changed the pump on it, so don't know where it was.. It wasn't my car, so I never paid much attention to it under the hood.. Normally, at 147k miles, the radiator would be nearing last legs with clogs, but maybe it's semi ok being you kept it fairly clean. MK

Reply to
nm5k

Hey there!

The thermostat was replaced by my mechanic about 3 years/15k miles ago, likely using a non-OEM part. The sense I get from the temp gauge is that the car does try to maintain 40% max temp, so the thermostat is probably working ok.

About 5 years ago my buddy and I drove the Corolla up Mount Washington in New Hampshire (highest peak in the Northeast) and back then I remember the temp gauge would hit about 75% max before the cooling fan kicked in. Since we were climbing up extremely steep grades I didn't think anything of the temp. Unfortunately, I forget how the temp behaved when on the highway.

The timing belt was replaced by the first owner in '97 when the car had 90k miles. He didn't replace the water pump. When I bought the car (1999, 94k miles), I fretted about the water pump for a long time, worrying it would fail soon. I called some local shops that told me something like $400 to do the timing belt, $400 extra to do the water pump-- they said it wasn't an overlapping job. Anyways I ended up doing nothing, not knowing how long the car would last. Right now I'm kind of trying to avoid sinking a lot more $$$ into the car since I just did so last year replacing a lot of worn-out parts to keep the car in perfect shape. For now I think I'll just flush the coolant myself since it's cheap to do this as a first step, and will see how the temp gauge behaves. In an IDEAL world I'd replace the waterpump myself, but unfortunately I don't have the skills or tools to do it.

Took another 250 mile drive today-- temp still behaving the same-- drops instantly if I downshift (the automatic) and raise the engine RPM. With the heat on even just a bit the temp gauge is always 40% max, but I can't keep the heat on year-round obviously.

The car ran and rode smooth, solid, beautifully as always. Has surprisingly good pull from 50-75mph in 3rd gear. The transmission is tight and flawless too. Cruises very quietly on the highway. It's one of the smoothest cars (of any size or age) I've ever driven. The car spent most of its life in Los Angeles, and afterwards garaged in the Northeast (now I live somewhere where it's too expensive to have it garaged, so it's been parked outside for a couple years unfortunately-- as per my other post re. that cracked windshield). The body and paint are great and better than some of the 2-year-old cars I see out there, and mechanics are shocked when they see what good shape it's in. Serious question-- would you or someone you know be interested in owning it someday? I may sell it within the next 4 months, or next year, depending upon my parking situation. My guess is book value is around $1000 and since it looks/runs great I might squeeze $1500 out of someone out there. The car is much, much too nice to be a beater, and I'm loathe to sell it to someone who's going to abuse it and drive it into the ground without maintaining it, but that is what people looking for $1000 cars do with $1000 cars. I'd rather sell it for less money to someone who would take care of it, but how do I accomplish this? There's no Toyota museum out there as far as I know, otherwise if they needed a Corolla SR5, I'd donate mine there so that it could live forever!

Anyways, my goal is for the car to be well taken care of and well-used by whoever owns it next-- if anyone has ideas how I can do this, let me know. The problem with my keeping it indefinitely is that parking spaces cost big $$$ in Boston so keeping an extra car costs a ton.

Take care! John

Reply to
johnyang97

IMHO you are describing a coolant system flow problem. Increased RPM's equate to a reduced temperature. I would say it's probably not the pump since you are experiencing normal temperatures except for a low RPM, high load condition, the fan cycling on and off. I would remove the radiator and take it to a radiator shop and have it "boiled out". It is a better method than just a "power flush". They will check the entire radiator's function. A radiator that old may have many tubes blocked / damaged, that will definitely reduce flow and cooling capacity, and you may have to have it re-cored or replaced. The blockage can occur very slowly and lead to your symptoms. Power flushing done at your local oil change shop usually does not include a flow check. Your heater core may be experiencing the same blockage as well. If you have an old or original cap, I would replace it as well. Good luck.

Reply to
user

Well, you could ALWAYS leave it with me in Greenfield... ;)

This is an interesting problem and similar to one I had with a Plymouth Grand Voyager.

When the engine was revving, I had heat...when it went into OD, I didn't. I took out the waterpump, and it was fine (pump was outboard of the engine).But I broke 3 bolts trying to get it out, and since the engine was in sad shape anyway, I scrapped it...

Reply to
Hachiroku

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.