Reason for coolant line bursting, not circulating, missing fan?

How-to's and repair secrets for your 4WD can be found here. Have a question? Ask it in here!
User avatar
JMack
Newbie
Posts: 14
Joined: Tue Mar 19, 2019 8:22 pm
My tercel:: 1985 Toyota Tercel SR5 Wagon, Manual with Weber carburetor
Location: Montpelier, VT

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by JMack »

It also looks like coolant is seeping out of the top of the radiator
You do not have the required permissions to view the files attached to this post.
User avatar
JMack
Newbie
Posts: 14
Joined: Tue Mar 19, 2019 8:22 pm
My tercel:: 1985 Toyota Tercel SR5 Wagon, Manual with Weber carburetor
Location: Montpelier, VT

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by JMack »

Unplugged radiator fan and it went right on when starting the car, so does that mean the thermostat was causing it not to turn on, or do these mechanical fans run anytime the car is on?

The radiator also sounds like it's sizzling--does this mean there's a leak? Or that it was clogged with debris which caused a leak? I haven't opened the radiator cap yet but I was going to check the coolant level once it's completely cool.

Also while I was checking the fan, I noticed (maybe for the first time) that there's white smoke from exhaust. Does this seem pretty likely to be the head gasket, due to the white smoke from the exhaust?
User avatar
dlb
Highest Ranking Member
Posts: 7305
Joined: Mon Jul 06, 2009 9:03 pm
My tercel:: '87 sr5, '83 dlx parts car
Location: bc, canada

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by dlb »

JMack wrote: Mon May 31, 2021 12:39 pm Radiator fan is not working!
You beat me to it -- yes, if the fan runs when you unplug the coolant temp switch, the fan is good. That means you probably just need to replace the coolant temp switch. Easy and cheap.

The coolant at the top of the radiator, that is usually caused by a leak at the upper rad hose, or it could be a leaky rad cap. I've never seen radiator seals wear out. It sounds like you replaced the upper rad hose recently so I would make sure the clamp for it is done up snug, and you may as well replace the rad cap since they're only like $5. A leaking cap would certainly hiss.

A small amount of white vapor on startup is normal but if you're seeing clouds of white, then yes that indicates a leaking head gasket. Get a compression tester and check the compression on each of the cylinders. If you have low compression on two of the cylinders, that is where the head gasket is leaking. I would sort out the radiator issues first though.

The climate control switch is easy to replace as long as you can find another one at a wrecker or buy one from a member here. And I doubt the heater core needs to be replaced -- if it did, you would have pools of coolant leaking from it, either inside or outside the car. Very noticeable. Using a water hammer-like tool to clean out scale and buildup is all that is necessary. More info on that here:

viewtopic.php?f=10&t=9589
User avatar
JMack
Newbie
Posts: 14
Joined: Tue Mar 19, 2019 8:22 pm
My tercel:: 1985 Toyota Tercel SR5 Wagon, Manual with Weber carburetor
Location: Montpelier, VT

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by JMack »

Any recommendations for a compression tester? I read on here that someone needed a 20mm adapter, but it looks like most online go up to 18mm.
User avatar
dlb
Highest Ranking Member
Posts: 7305
Joined: Mon Jul 06, 2009 9:03 pm
My tercel:: '87 sr5, '83 dlx parts car
Location: bc, canada

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by dlb »

Compression testers usually come with the two standard spark plug sizes, tercel's use a stand plug size so you shouldn't need to worry about finding another adapter. I just have a cheap one from Canadian Tire, not sure of the brand but it works fine.

I can't remember all the details of compression testing but I think they are that the engine should be warmed up, all spark plugs removed, and all the same # of cranks on each cylinder (I think it's 6-8 but am not sure). You can look these things up to verify them though, or they will be on the instructions of the tester you get.
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by Petros »

wow, I just saw this thread since I was away from the interent during the long weekend.

Please allow me to save you a lot of trouble, I have decades experience with the cooling system on the Tercel4wd. but first, sounds like you have a lot of irresponsible mechanics and DIYers who made a mess of this car before and since you owned it. keep it away from all of them, they clearly do not know what they are doing and are worse than a waste of many, they will cause you further damage and heart ache. Not to worry however, YOU can fix it yourself correctly. and save yourself a lot of money and trouble relying on incompetent mechanics (they should have just admitted not knowing anything about this car rather than take your money and NOT fix it!). most of them were likely not even born when this car was new.

Once you have overheated this engine, even once, you will almost certainly need a new head gasket, and if badly overheated likely the head is warped too. this does not always show up in a compression test, but will seem to run okay, but start consuming coolant after it warms up. hence, why it keeps overheating. the coolant is turning to steam and going out the exhaust. until it totally fails, it may seem to just run fine, but you are loosing coolant.

You must get the tools and supplies together I list over in my thread on replacing the head gasket in the repair guides section. it is a big job, but you can do it in an afternoon if you have all the correct tools and gaskets/supplies available, as I list in the head gasket replacement instructions. it is also a good idea to replace the exhaust valves while the head is off, they can get heat damaged (you can not tell by looking at them) and they can disintegrate after you get it running. it will do a lot of damage to the head and engine when they do break apart. not worth the risk, unless you know they have been replaced recently during other engine service.

also, make sure you get the cooling system completely checked out, the original reason it overheated can still be in the system, make sure you find and fix it when you replace the head gasket Always replace the original unknown thermostat with a good quality new one (not a cheap, $9, communist made POS that is junk out of the box, only get a USA or Japanese made thermostat, should cost about $20 to $28). replace or repair a leaking radiator (those plastic top radiators are risky after about ten years, the plastic breaks down and can let loose all at once in a whoosh...and leave you with another fried head gasket, I know, I have done it...and now hate those plastic radiators). an all metal radiator is best, but hard to find and more costly, I think worth it if you plan to keep it running indefinitely. other wise a new aluminum one with the plastic head tanks will do as long as you plan to replace it every 80-100k miles or ten years (I have over 400k miles on mine, it is on its fourth radiator, clutch and engine overhaul now). the plastic top radiator is a disposable component AFAIAC, like hoses and belts.

do not let anyone tell you the water pump might not be circulating, it has happened, but it is extremely rare to have a an outwardly good water pump not circulate coolant. Normally when they do go bad, it is usually with a blown seal that sprays coolant everywhere and a bad wobbly bearing. if there is any leaks from the water water pump shaft seal, or any wiggle in the shaft, buy a new one, NOT rebuilt (those too are junk right out of the box), usually you can buy a brand new one for only a little more money from NAPA or Rockauto. If you need one, buy only a Japanese made water pump for the tercel, they are only like $39 and well worth it.

carefully check all the hoses, heater and upper and lower radiator hoses. especially the upper one, it is the hotest and under the most pressure (the lower rad hose has a vacuum on it). Again, any questionable hose is not worth the risk, you can buy good name brand hoses from rockauto at very reasonable prices, otherwise Autozone or NAPA can order a good Gates one for you for more money. Good ones should last 10 plus years, so well worth it. also replace any remaining wire factory hose clamps with stainless band clamps, the factory wire clamps are not reusable. if you have any of the newer type spring clamps, if not bent they work fairly well too.

you also might consider giving your heater core a vinegar soak to clear out any scale and deposits. it will make it more effective heater and also will act as an emergency auxiliary engine cooling mini radiator if necessary. you remove the heater hoses, flush with water, fill with white vinegar and let site for 30 min, and than flush it wout with clean water (I like to run an outlet hose into a bucket to catch the flush out to see what comes out, usually I get white flaky deposits).

Usually the factory temperature gauge and sender are fairly reliable, but occasionally the sender (it is on the front of the head) goes bad. so make sure it is working so you can monitor the temp carefully until you have it sorted out. you would not want to overheat the new head gasket you install soon after the job is done. a trustworthy temperature gauge is essential. if in doubt you can buy a cheap aftermarket temp gauge at the auto parts store to double check the factory one, a bit of trouble but worth the piece of mind if you question the factory temp gauge in the dash. new senders do not cost much, but no reason to replace the original one unless you suspect it is bad.

Do these things, and it will not overheat again, flush and replace the coolant about every 3 years, and you might also install a new quality thermostat at the same time as a preventative measure. every three t-states, consider a new plastic radiator if you have that type. and it will run forever if you keep all the other fluids changed at proper intervals.

Good luck.

if you have any questions, feel free to ask.
'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)
User avatar
JMack
Newbie
Posts: 14
Joined: Tue Mar 19, 2019 8:22 pm
My tercel:: 1985 Toyota Tercel SR5 Wagon, Manual with Weber carburetor
Location: Montpelier, VT

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by JMack »

Thank you so much for your thoughtful response, Petros. And thanks to everyone else for responding as well.

I did order a good thermostat but haven't had time recently to do much (still in the process of settling in here in Vermont).

I'll work on gathering the right tools.
User avatar
Petros
Highest Ranking Member
Posts: 11930
Joined: Sun Jan 28, 2007 6:31 pm
My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by Petros »

here is the link to the head gasket repair/replacement instructions:

viewtopic.php?f=7&t=6059
'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)
xirdneh
Highest Ranking Member
Posts: 2121
Joined: Thu Aug 04, 2005 11:38 am
My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by xirdneh »

If it was ran for a long time without antifreeze the water pump impeller can rust away to nothing. Its rare but i have a friend with a tercel and he did it.

Also that ac switch you mentioned. Tercels with ac have a switch on left side of heat control panel. If it was removed its not needed to get heat. The heater fan is controlled only by lower left lever type switch. If fan does not run it may need new brushes.
Love those Tercell 4x4 wagons but they sure suffer from road noise.
User avatar
dlb
Highest Ranking Member
Posts: 7305
Joined: Mon Jul 06, 2009 9:03 pm
My tercel:: '87 sr5, '83 dlx parts car
Location: bc, canada

Re: Reason for coolant line bursting, not circulating, missing fan?

Post by dlb »

xirdneh wrote: Fri Jun 04, 2021 1:05 am The heater fan is controlled only by lower left lever type switch. If fan does not run it may need new brushes.
Or if the fan only runs on certain speed settings, the resistor pack just needs some simple repairs. It's easy to access.
Post Reply