Overheating saga..

General discussion about our beloved Tercel 4WD cars
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stefando
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Joined: Sat Apr 28, 2018 9:14 pm
My tercel:: The Caribou: 1983 SR5
Location: Norcal

Overheating saga..

Post by stefando »

Hey all,
So I have an 83 SR5 all stock everything, OE replacements, Georgia emissions (minimal). Last year in the spring I noticed the radiator was leaking and so I replaced it and the thermostat. Fast forward to August this year, 110 degrees F for 3 weeks and I noticed that the temp gauge was hanging out higher than I remembered it, not overheating but just hanging out at the line sometimes. Figured, hell it's hot out I'll drive easy and watch it. No problems but in September it overheated slightly. So I read on here about crappy t-stats and ordered an aisin, replaced it and it seemed to help a little. Didn't overheat at all for a while, but then I noticed at slow speeds it would start to get hot. Fan works fine. Finally it overheated a little bit, just over the line a bit. I stopped and popped the hood and the top coolant hose was a little pressurized (maybe some people wouldn't have noticed, it was just a little firm). I waited till it cooled down, then drove home (5 miles). It was fine until my hill to my house and then overheated again. So I checked everything as I saw on here to try and diagnose it, coolant was clean, oil looked great, fan starts, thermostat worked before I put it in. A friend says "Head gasket" which I thought well, it hasn't been opened up in fifteen years (!) timing belt is due now (60K on old one) so I'll do the water pump and the timing belt. Opened it up and the pump looks fine, no leaks, spins right no missing teeth. Did find a valve cover leak so I pulled the cover and the oil looked brown sorta. I don't have many resources here but I do have a head gasket kit so I said, I'll pull this head and see what's up in there. Petros maybe wouldn't approve of my poor diagnosis skills... So I pulled it off and the exhaust valves were trashed, sorta fried. Good I thought, I'll swap em and clean things up. BUT the head gasket looked totally fine, no visible leaks between ports. I know there could be something I can't see but I was kinda shocked with how good it looked. So I'm doing petros method replacement and it will have a new water pump, timing belt, etc... but I'm concerned that maybe it will still have the same problem after and I don't want to ruin the new head gasket with an overheat. No lights come on, so I'm not sure about the oil pump. Should I just order one and stick it out another week while I wait? I need the car on the road... Could all this be from a crappy radiator? It only overheated at slow speeds with high load, highway speeds and it was perfect... Anyway, friend is doing the valves, seats, guides and I get it back tomorrow ($60 bucks!) Any help is appreciated. My dad says likely a head gasket leak I couldn't see and not to worry about the oil pump just yet.. I know I need to get a pressure gauge asap. Thanks everyone.
1983 SR5 Brown
Salmon River California
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splatterdog
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Re: Overheating saga..

Post by splatterdog »

Low speed overheat usually means the rad has poor heat transfer. Combustion leaks are usually worse the harder you drive it. If you remember what car exhaust smelled like before catalytic converters, smell the inside of the rad for a similar odor. If there is a gasket issue, the spark plug will be extra clean on the affected cylinder.

Belt loose or glazed?
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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: Overheating saga..

Post by Petros »

sounds like a compromised head gasket based on its behavior. A leaking head gasket is hard to tell except that it uses coolant. sometimes it is just a little at first, like a cup or two a month. But it will continue to get worse if not fixed. Getting the engine up to the edge of the red zone on the temp gauge usually is enough to compromise it, but it may take 3 to 6 months to show up.

You say you replaced the radiator, was it a new one, or one from a wrecking yard? was it the single row core, or does it have double row of coolant tubes? the single row core is about 5/8" thick at the edge, the double row is typically about 1.5" core thickness. Single row radiators cost less and are often sold as a replacement for the T4wd, but these are only for the 2wd sedan. It will not have enough cooling capacity on summer days at fwy speeds when going up a long hill, particularly if it is filled with luggage or other cargo.

The oil pump is completely unrelated to cooling, it sends lubricant to the internal moving parts. if it is badly worn you will trash the bearings and cam and it will never even get hot. If you are worried about the oil pump you will need to install an oil pressure gauge and watch it as you drive. you can buy an inexpensive oil pressure gauge and just rig it up as temporary diagnostic tool, tape it to the lower edge of the dash and watch it as you start and drive it from cold, to fully warmed. But I doubt that is your current problem, and even if oil pressure is low it will have no impact on coolant temperature and it would be a separate unrelated issue.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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stefando
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My tercel:: The Caribou: 1983 SR5
Location: Norcal

Re: Overheating saga..

Post by stefando »

Radiator was new from the interweb, spectra 2 row. Definitely not the most expensive one available but it was pretty similar to the one that was in there (which worked even though it leaked, just smelled an awful lot) I suppose this could be a bad unit out of the box? bad switch? Thanks for the quick response, as for the oil pump, I'll get an oil pressure gauge one of these paychecks just to see what's going on. It did consume maybe a cup of coolant, not much more than that in the last few months. Definitely don't want to dig into the bottom end if I don't have to.. but I'd like to keep this engine alive until I can get and rebuild a 4AC.

Splatterdog, I thought it was strange too that it didn't overheat with high revs, it would be a shame if a crappy radiator blew my new head gasket... maybe I should spend another 80 bucks to be sure.. seems paranoid though.

One other thing, I'm looking forward to getting the head back and putting some ping reduction grooves in... I get what I consider too much pinging (which might have been the toasted exhaust valves?) even with good gas, suggested 10 deg advance, meticulous vacuum examination and a good new diz and wires. Been told by a local Brat enthusiast that's just the way it will be but I tend to think the local subaru crowd has learned to deal with resolvable issues.

I'll post here with a post-head install update to close this story (hopefully!)
1983 SR5 Brown
Salmon River California
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Petros
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Re: Overheating saga..

Post by Petros »

if you are getting a lot of ping you may have to go to mid grade, or premium, fuel. costs more, but if you have a pre-ignition problem that usually takes care of it, and you get a bit better fuel economy so your net cost is about the same per mile, plus you do not compromise head gaskets.

A lot of ping will also compromise the head gasket, that might be your problem right there. better track the cause of it down, make sure you are setting the timing correctly (follow procedures), and no vac leaks, fuel system working properly, etc.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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simon84
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Re: Overheating saga..

Post by simon84 »

I had pinging that was caused by the crankshaft timing gear wearing out the keyway (notch for the woodruff key) which set the valve timing off. May not be your issue but might be worth checking. It`s not a bad idea to pull the crankshaft gear and do the seal while you are in there and you`ll be able to tell if it`s an issue.
Driver: 87 Tercel SR5, white, 4ac, weber carb (aka the Tercedes)
Road Tripper:95 Mitsubishi Delica L400 2.8L Turbo Diesel
Motorbike: 94 Kawasaki Ninja ZX6
Project Car:Red 68 Plymouth Sport Fury III
Previous Tercel:Orange 84 Tercel 4wd (aka the pumpkin)
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stefando
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My tercel:: The Caribou: 1983 SR5
Location: Norcal

Re: Overheating saga..

Post by stefando »

Hey everyone: I've been slow at posting because well, I'm still at it... Head went in smooth, timing belt, tensioner, water pump thermostat.. everything back together. Put the distributor in at TDC and it started nice. The thing is, it's like 15 degrees after TDC so I assumed it was a tooth off and pulled the distributor and tried a tooth in that direction. Car wouldn't start. So for the last 3 days I've spent a total of maybe 6 hours trying different distributor settings, carb settings, got help from a local guy this morning and eventually he agreed we should just put it back where at least it starts. But it's so far off that the car doesn't have any power uphill and overheats quick.. so I don't want to blow the new head gasket and I try the same things again. I've even pulled everything back down to the bare timing belt to make sure that it was set correctly.. did that twice... Only starts on one tooth setting for the distributor and only when rotated all the way advanced. Then the light shows 10-15 degrees after no matter what- adjusting the carb only makes it further out of time. I'm about to lose it... Any advice would be helpful...

Note: All vac lines are stock and checked over
timing belt is on correctly
car ran perfectly before head gasket job (just overheated)
distributor advance works (it will bring it almost to 5 degrees AFTER TDC)
1983 SR5 Brown
Salmon River California
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rer233
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Re: Overheating saga..

Post by rer233 »

Had a similar problem years (decades) ago with my first Tercel wagon. Car had low power when I bought it, and I couldn't get the spark timing correct no matter where I indexed the distributor. Turned out the cam timing was off a tooth. I know you said you double (triple) checked cam timing, but did you use the mark on the crankshaft gear or the zero mark on the balancer? If the balancer, it's possible the outer part of the balancer has rotated slightly with respect to the inner hub due deteioration of the rubber damper. Easiest way to check the balancer is with a top dead center stop- you can make one by knocking the guts out of an old spark plug, chasing a thread inside it,and screwing a bolt into it. Then pull #1 plug, get #1 piston close to TDC, screw your "new" tool in and GENTLY turn the crank clockwise 'till the piston contacts the bolt and mark the balancer where it lines up with the zero mark on the timing cover. Then, without disturbing anything, rotate the engine counter-clockwise (again, GENTLY) 'till the piston again contacts the bolt. Mark the balancer where it lines up with the zero mark on the timing cover now. The spot midway between your 2 marks is your true TDC.

Good Luck- hope this helps.
if it aint there, there's a good chance it won't break!
83 SR5 Silver/Blue (Snowmobile/work beater)-totaled but drivable
85 SR5 Blue
88 SR5 White (the 'good' one)-not anymore-totaled
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jimcrazy
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Re: Overheating saga..

Post by jimcrazy »

couple of pics,where the rotor button should be when installed,also after installing the the dizzy turn the rotor button by hand and make sure the mechanical advance is working,,it should spring back on its own if not it is seized up and will need to be freed up
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jimcrazy
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Re: Overheating saga..

Post by jimcrazy »

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stefando
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My tercel:: The Caribou: 1983 SR5
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Re: Overheating saga..

Post by stefando »

rer233 wrote: Tue Nov 20, 2018 6:11 pm Had a similar problem years (decades) ago with my first Tercel wagon. Car had low power when I bought it, and I couldn't get the spark timing correct no matter where I indexed the distributor. Turned out the cam timing was off a tooth. I know you said you double (triple) checked cam timing, but did you use the mark on the crankshaft gear or the zero mark on the balancer? If the balancer, it's possible the outer part of the balancer has rotated slightly with respect to the inner hub due deteioration of the rubber damper. Easiest way to check the balancer is with a top dead center stop- you can make one by knocking the guts out of an old spark plug, chasing a thread inside it,and screwing a bolt into it. Then pull #1 plug, get #1 piston close to TDC, screw your "new" tool in and GENTLY turn the crank clockwise 'till the piston contacts the bolt and mark the balancer where it lines up with the zero mark on the timing cover. Then, without disturbing anything, rotate the engine counter-clockwise (again, GENTLY) 'till the piston again contacts the bolt. Mark the balancer where it lines up with the zero mark on the timing cover now. The spot midway between your 2 marks is your true TDC.

Good Luck- hope this helps.
I have the upper timing cover off so I can shine a light down on the crank timing sprocket- I've been lining this dot up with the mark on the block as shown in the fsm. With this cover off I can then look through the cam gear hole and see the carot (^) in the window. I'm going to follow all of the vac lines again tomorrow, for now I've got to make some Sourdough. I've been concerned that maybe I just haven't found the right carb settings for it to start on the right distributor setting.
1983 SR5 Brown
Salmon River California
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Petros
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Re: Overheating saga..

Post by Petros »

but it does not sound like a carb problem, that does not affect the timing. setting the distributor close enough to start is not that difficult, though a simple mistep can be very frustrating. Best thing is to double check all of your assumptions, think through the whole distributor installation, and than reinstall it so the rotor is pointing where shown in the picture by Jimcrazy (the rotor should point at the round logo on the coil housing when it is all the way down). This should always be close enough to start.

Also, double check you have the spark plug wires in the corrector order and plugged in (sounds dumb, but that is an easy mistake to make...I have messed this up more than once even after working on old cars for over 40 years).

Make sure the mechanical advance is free (rotate the rotor, it should return back to where it started), lube the mechanism.

Make sure you pull and cap off the two (or three) vac lines to the distributor to check/set timing. after you set it than you plug them back in. you might test each vac diaphragm my putting a vac line and sucking on it to make sure it is not ruptured (it will act like a vac leak). If bad, just cap it off at both ends (it will run fine without it, it is only used to advance the spark at part throttle positions to improve the economy slightly).

Make sure you still have spark, sometimes you may have harm a marginal connector and not realize it.

Have confidence you will sort it out, even if frustrating to isolate the problem. likely you will find it and it will be an easy fix (and perhaps feel dumb for not finding it sooner, we have all done that too). YOU CAN FIX IT!

Good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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stefando
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My tercel:: The Caribou: 1983 SR5
Location: Norcal

Re: Overheating saga..

Post by stefando »

Thanks Petros, and rer and jimcrazy and everyone else- The car has been timed. I had it a tooth off at the distributor, I guess I just was missing a tooth every time I tried, really easy to get it one late. There was also a crack in one of those plastic vacuum filters, and I swapped that with a solid piece of tubing for now and that helped everything quite a bit. The carb was adjusted really crazy to compensate for some leaks in the manifold gasket so getting it set after the car was timed right has been interesting. I can't get it to idle lower than 1000 RPM (Idle screw min.) but the timing is right on so I can live with that for a bit. I'm really glad I had this opportunity to take the head off and change gaskets, o rings, belts etc.. There's something triumphant about this car and Petros is right: You can fix it! I'll take the car out for a rip tomorrow morning. Thanks everyone.
1983 SR5 Brown
Salmon River California
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Petros
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Re: Overheating saga..

Post by Petros »

Good for you! you will have something to be grateful about on Thanksgiving day.

You can enjoy the turkey on your plate, and not the one under the hood.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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ARCHINSTL
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Re: Overheating saga..

Post by ARCHINSTL »

stefando wrote: Wed Nov 21, 2018 10:22 pm There's something triumphant about this car...
NOT diminishing any of your work or the others' help, but quoted above is how so many of us feel about our little guys!
Your best line!
Tom M.
T4WD augury?
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