[BonestockNA]

Hopefully its just a leaky hose somewhere. Agree that heater core jobs are no fun.

Back in the day I installed Pennzoil 10W40 all the time in the NA engines. Now I'm running Pennzoil 10W30. Oil specs have greatly improved over time and viscosity breakdown is far less of a thing now.

I still have the OEM copper radiator so I'm also running old school Peak green coolant. My radiator cap orings are on the way out so when I replace the radiator I will be replacing with an Al core. At that point I will use a more advanced long life red coolant like Toyota Red. I used red before with a Cu core radiator and did not get good results.

 

[3p141592654]

I've used Toyota Long Life Red (concentrate) with great results. It was the factory fill in 1986-92 and is compatible with the brass and copper in the 7M and has phosphate for ferrous metal protection. The later premixed Toyota Super Long Life Pink (a HOAT coolant) would be a poor choice in a cooling system with any brass/copper. What issues did you have with red?

 

[BonestockNA]

This bad experience with a red coolant was on a 92 Camry 3VZ-FE. About 20 years ago the original Al core radiator gave out at a very bad time and I was forced to replace it quickly with the only radiator I could get my hands on immediately which was Cu core. Red coolant came out of the car and I replaced it with what was more than likely a red OAT coolant I picked up at a local store. The new radiator only lasted about another 5 years, the acidity ate up the Cu. Once that happened I realized that the coolant was the issue and I flushed, went back to Toyota Red which was what the car came with. At that point I was able to find an Al core replacement. That same car was passed to a family member who still drives it.

20 years ago there was a lot of confusion out there about the new long life coolants and how they were all formulated. The GM Dexcool saga was a good example of that confusion. I still find GM cars cracking composite water manifolds because of the wrong coolant.

I decided last year to put in a conventional green coolant that was low silicate because that's what came out of it and I remember new late 80's Supras having green coolant. I will be flushing and filling with Toyota Red when I change the radiator to Al core.

And you are so right about the Fe protection. Most coolants in stores now are for all Al engines. I was involved with a discussion on this last year and I think we wrote a small PhD dissertation on the subject by the time we were done.

 

[te72]

Like wise man say, there's two kinds of cars in this world. Cars that go fast, and cars that don't leak.

I must have a garage full of ridiculously fast cars then.

 

[sturi0_]

I think I found the culprit. Behind the head near the fire wall, I see some drips falling and I managed to take a vide. of the small leak. I can upload it to google drive if you guys would like a video. But tbh, this looks like its enough. Could this be a heater hose job?

the brown thing is the small drip

Photo with no drip

On my way home, a friendly driver let me know there was a bunch of smoke underneath my car and it smelt like sweet caramel on the way home. This must be a heater hose job, no? Im gonna buy parts as soon as I get an opinion.

 

[3p141592654]

That is the famous 90 degree bend hose. There is another at the front of the motor. Both get cooked by the exhaust and fail. Suggest replacing both. The heater hoses are also back there but are not that one.

 

[sturi0_]

That is the famous 90 degree bend hose. There is another at the front of the motor. Both get cooked by the exhaust and fail. Suggest replacing both. The heater hoses are also back there but are not that one.

Damn. Do you have a link or website to where I can find a replacement (preferably an upgrade)? Or will I have to search ebay 😭

 

[Asterix]

For that hose, and the #6 bypass hose (16283 in 3p's diagram), take your old one to your local parts store and poke through their hose collection to find one with the right bend you can cut out and use. That's the cheapest way to go.

The fun part for #6 is you have to remove the distributor/cps to get to it.

 

[BonestockNA]

I found all of those formed hoses on RockAuto.com. Gates makes a lot of them and you might have to mix in a Continental or AC Delco to complete a full set. They are reasonable.

 

[sturi0_]

I found all of those formed hoses on RockAuto.com. Gates makes a lot of them and you might have to mix in a Continental or AC Delco to complete a full set. They are reasonable.

Do I select any of the few hoses on the "coolant hose / pipe" drop down menu and cut it up to fit the 90 degree hose?

 

[OldBonus]

Do I select any of the few hoses on the "coolant hose / pipe" drop down menu and cut it up to fit the 90 degree hose?

Yep, just cut them to fit.
Your local O'Reilly also carries the Gates 90 degree hose but will cost more.

 

[BonestockNA]

Go back to the RockAuto site and look under heating and air conditioning. There is a hose section in that part too:

I mixed and matched all my hoses from there and when they arrived they were all direct fits. No cutting needed. Time to change all those 30+ year old hoses and clamps. I was happy to find all of them pretty easily.

 

[sturi0_]

I mixed and matched all my hoses from there and when they arrived they were all direct fits. No cutting needed. Time to change all those 30+ year old hoses and clamps. I was happy to find all of them pretty easily.

Im lowk gonna run the 7m to the ground until I attain a 7mgte / jz / uz, this'll come in handy once the leaks appear lol.

 

[sturi0_]

Alright here's an update to the people searching for post headgasket or coolant hose leaks in the future and simply want to know what happened after this thread;

I actually found several hose leaks. One of them was from the union hose (the hose that connects the 90 degree hose located above the engine as seen in this famous video) and the hose that goes from a heater hose to the throttle body.

It kind of explains the rough idling I've been getting recently and all of my missing coolant. It does not explain why my oil has been eating up, however after some time I figure my piston rings are fried. Or perhaps its a result of the ECU going poopoo because of the throttle-body-to-heater-hose leaks.

Last bit of beginners advice to a mk3 owner trying to get their 7m rebuilt;

Replace all of the hoses. Whether or not its a random ass hose from oreillys or rock auto or whatever, just replace all of them (but keep the spring clamps. theyre pretty good quality and you can always have the left over). If theyre not in terrible condition you might as well wait until they are blown but definitely replace all the hard to reach hoses.

I still need to do a compression test...