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Misael

Radiator/Cooling Help

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What's up fellas? Do you guys recommend upgrading the radiator and cooling system? And if so, anybody know where to look for one and get one for my 79' Corolla with a 2TC. Thanks!

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Hi Misael,

                 Is your current coolant system setup over heating, or losing water ?

Have you done all the regular coolant system maintenance, like replace thermostat & radiator cap ?

Has the radiator core been cleaned professionally ?

Changed coolant completely ?

Checked water pump, fan belt, or replaced ?

Has there been any performance mods been carried out on your 2TC, that may have added heat load to the coolant cooling system ? 

If all above has been carried out, & you still have issues, a 3 core aluminum radiator with an aftermarket thermofan, will greatly help.

How hot does it get to in the area/location in Arizona, where you use your Rolla ?

Cheers Banjo

Edited by Banjo

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15 hours ago, Banjo said:

Hi Misael,

                 Is your current coolant system setup over heating, or losing water ?

Have you done all the regular coolant system maintenance, like replace thermostat & radiator cap ?

Has the radiator core been cleaned professionally ?

Changed coolant completely ?

Checked water pump, fan belt, or replaced ?

Has there been any performance mods been carried out on your 2TC, that may have added heat load to the coolant cooling system ? 

If all above has been carried out, & you still have issues, a 3 core aluminum radiator with an aftermarket thermofan, will greatly help.

How hot does it get to in the area/location in Arizona, where you use your Rolla ?

Cheers Banjo

Hey Banjo,

No overheating going on but I was wondering if it would be a good idea. We had the hottest summer this year. 110+ farenheit for 50 consecutive days. It was terrible. I plan on getting a new carburetor, headers with custom exhaust my friend will make for me. That's probably all I will do to my Rolla for now. I haven't done any coolant maintenance yet because I wanted to ask first if it was worth just upgrading everything instead.

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Hi Misael,

                  Woo !  110+ F for 50 consecutive days.  I know Arizona is a hot state, but that's pretty extreme. That's why I asked.  Here in Australia, in the interior desert areas, we have similar places with records like that.  I once worked at a place in Western Australia, (Marble Bar) before Australia went "metric" to Celcius, where it held the Australian record for 100 consecutive days, with the temperature never dropping below 100 deg F. night & day.

Coolant/engine temps are a very misunderstood parameter.   Engines are designed, such that the block in particular, is held at a reasonably narrow ideal temperature range, to allow all clearance dimensions to be, "as designed".  If an engine runs at temps for prolonged periods, either above or below this band (typically 175 - 195 F / 80 - 90 C) then there are consequences.

That's why it is important, that an engine warms up quickly, before you put it to work.  One of the real reasons, taxis get such very long engine lives, is that typically, they never get cold, as typically three drivers doing 3 off 8 hour shifts, results in the taxi, never getting cold.

Coolant systems often get neglected, but attention to all the components of the coolant system, I mentioned earlier, are important. When we are working with engines as old as our Rolla engines are, especially with cast iron, & alloy components, the problem of coolant passage corrosion can be severe.

The best thing you could possible do to your Rolla, is replace the original brass/copper radiator with a aftermarket 2 core aluminum one.  Here in Australia, they are freely available on ebay, at around AUD 200+.   https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=corolla+KE+radiator&_sacat=0    I presume you have access to something similar in the USA.  If not, then find a late model aluminum radiator, that fits, from another younger car.  Toyota/Nissan/Mitsi

The efficiency of an aluminum alloy radiator, (in terms of removing heat) compared to the OEM originals, is like chalk & cheese. One of the best things I ever modified on my 43 year olde Rolla was fit an aluminum radiator.  The second best thing I did, was get rid of the mechanically driven fan, that sucks so much power from the engine, & fit a thermofan.  If you can find a late model radiator, from another car, that already has an integral thermofan, then you have "killed two birds, with one stone", so to speak.

Cheers Banjo

 

   

Edited by Banjo

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Yes, as Banjo says, alloy rads do help. The radiator is half the weight of the copper one, yet holds twice the water, so overall the full radiator weighs the same. The electric fan means more bhp for the wheels as it rarely turns on, but also makes the motor a lot quieter. It also takes the stress off the water pump bearings from having a heavy fan hang on the front of them.

Make sure you run coolant, not because it raises the boiling point so much, but because it has corrosion inhibitor in it. If you ever have the head off the motor for a valve grind, (when you fit the carbs & extractors) get the block out too and clean the rust scale out of the water jackets. Its amazing how much crap builds up around the back cylinders & insulates them from the cooling water.

Tridon make a range of common thermostats in high-flow variants, you could chase up those too.

Just be careful getting the nuts & bolts apart in things like water pumps & thermostat housings, they corrode with rust and alloy corrosion which means they break off easily.

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Hi Misael,

                 Altezzaclub's comment . . . .

Quote

get the block out too and clean the rust scale out of the water jackets

is an important one.   The obstruction in water jackets in the block & head, severely hinder coolant movement, from getting to where it needs to be, around the cylinder walls.  A good professional engine builder, will always remove all welch plugs, and chemically & pressure cleanout all the "crud", inside. I make it a rule, to always knock out the welch plugs, & clean out the "inner sanctums" of the block, when I have a block out on the bench. Most manufacturers use steel welch plugs, usually zinc plated. However, even the zinc plated plugs eventually rust.

I've been amazed often, that an apparently good looking welch plug, can be incredibly thin, with corrosion, from the rear.  To assist in removing a welch plug, I have always drilled a hole through the middle, or hit in the middle, to release a bit of pressure on the welch plug walls.  The number of times, the drill or punch, has just broken through easily, has enforced my views on this subject.

When replacing welch plugs, I always use brass ones. They don't rust or corrode as easily.  Factories use zinc plated steel, because they cost slightly less, & they freeze them, before insertion, to achieve a tighter grip.  Many object that the softer brass ones, don't have as much holding tension.  However, if brass welch plugs are used, with a good quality hardening sealer, designed for this application, then that is the way to go.

The other consideration is the way you install the plug. The very best way, is to use a correct size dolly, that allows you to tap in the plug, on the outer edge.

Most engines suffer from unequal cylinder wall temperatures.  The coolant flow entering & exiting the block/head at the front, usually results in the rear cylinders always running hotter. Unfortunately, the lower flows at the rear, result in more crud building up at the back of the engine. In our K series engines, it is easy to have coolant temps at no: 4, being up to 15 deg C, higher than those at no: 1.  K series owners, will attest to this, with many experiencing, the plate on the back of the head, rusting out.

image.png.db8ad76e4d0c82dbb3ef72c618078ce9.png

  I've taken these plates off previously, & it was totally blocked behind it, with crud & corrosion.  I've fitted a coolant outlet to the plate at the back of my engine, & externally returned the coolant to the thermostat housing at the front of the engine.

image.png.07ebb30b0da1ed5abff0cacbd961c732.png

It lowered the differential coolant temp, between front & rear of the head, to just a few degrees C.

Cheers Banjo

 
Edited by Banjo

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Thanks a lot guys for the information! I'll probably end up doing a flush for now because I don't know when the last time that was. Plus that's quick and easy for now. I've only put about 300-400 miles since I've owned it. Should I change the thermostat now or wait until I upgrade the radiator and clean out the whole system like you guys are recommending?

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Thermostats are easy to remove & test.  Put it in a saucepan on the stove, & heat the water up from cold, until is just starts to boil.  If you suspend it, in the saucepan, you can clearly watch it open.  If that works OK, that's one thing to tick off your list. The thermostat it such a relatively inexpensive replacement part, that many people, including myself, just replace them, every 3-5 years, as a matter of course, & upgrade to one of the Hi Flow models.

Cheers  Banjo

Edited by Banjo

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On 10/16/2020 at 5:59 PM, Banjo said:

Thermostats are easy to remove & test.  Put it in a saucepan on the stove, & heat the water up from cold, until is just starts to boil.  If you suspend it, in the saucepan, you can clearly watch it open.  If that works OK, that's one thing to tick off your list. The thermostat it such a relatively inexpensive replacement part, that many people, including myself, just replace them, every 3-5 years, as a matter of course, & upgrade to one of the Hi Flow models.

Cheers  Banjo

I think I'll just go ahead and replace the thermostat then because who knows if it's ever even been changed. What do you think about this one? I'm new to all this and this is my first car I work on so sorry for the dumb questions. Are you able to view the link?

https://www.rockauto.com/en/moreinfo.php?pk=4483842&cc=1274633&jsn=19

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Hi Misael,

                 Your link works fine !  The thermostats don't appear to be very expensive on-line there in the USA, so go for it.  Make sure you order a Hi-Flow model, as you live in Arizona, & make sure you get the exact model thermostat, that will fit your particular Toyota 2TC engine.

Quote

I'm new to all this and this is my first car I work on so sorry for the dumb questions.

P.S.  No question is regarded as being "dumb", on this forum.  We are all learning, every day.

Cheers Banjo

Edited by Banjo

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14 hours ago, Banjo said:

Hi Misael,

                 Your link works fine !  The thermostats don't appear to be very expensive on-line there in the USA, so go for it.  Make sure you order a Hi-Flow model, as you live in Arizona, & make sure you get the exact model thermostat, that will fit your particular Toyota 2TC engine.

P.S.  No question is regarded as being "dumb", on this forum.  We are all learning, every day.

Cheers Banjo

Thanks Banjo! I'll probably get to this next weekend. I should be fine just doing a simple draining of the coolant and then refilling, right? Should I drain it with distilled water to wash out the residue? Or drop a hose in the radiator to flush? I've seen so many ways on YouTube but I don't want to do anything that's going to cause damage.  

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I’ve recently stripped down two K motors. The amount of crud in the water galleries is astonishing. Intriguing how the water jackets in block and head are often separated by the head gasket.  I was looking closely at this the other day and assume this is to ensure coolant remains in the head, as the simple water pump impeller would struggle to maintain sufficient pressure if coolant could simply drop down into the block. Not sure about that. But otherwise, numerous head gasket passages were completely, or nearly so blocked. I have removed quite a lot by this point 
 

imageproxy.php?img=&key=0c66b6295cc839cf9EC1436D-AAAE-4082-8666-DFDAF993DB36.thumb.jpeg.5a55638880383dd09ea7050fd2af23c3.jpeg9C294380-219C-4B0C-AD72-518CC5BA8A63.thumb.jpeg.c9b115ac7e70c6c99e17abf4fa80e4bc.jpeg3E055628-85C4-4CBA-990B-23E73D637531.thumb.jpeg.f41eef08323ca3d58f3738c33db02edd.jpeg

Edited by parrot
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Oh yeah !  They can get extremely blocked, particularly towards the rear of the block & head, where flow rates drop.

Very early head gaskets for the K series engines, had coolant holes that perfectly matched the flow-thro matching coolant holes in the block & head.  Later head gaskets, from several manufacturers, blocked flow-thro holes in the head gasket around cylinders 1 & 2, to force the flow from block to head, to only occur at the rear two cylinders.  This was an attempt to assist the issues with higher temps at the back of the engine & head.

In Misael's case, if the coolant system, hasn't had a lot of attention for a long time, and there isn't the opportunity to do a complete strip down, I would suggest.

1.  Remove the radiator.

2. Remove top & bottom radiator hoses.

3. Turn off the heater water cock.  It wouldn't be needed in Arizona, me thinks.

4. Remove thermostat.

5.  With a hose, with as much pressure as possible, flush the system out. First in one direction, & then in the other.

6.  Like wise flush out the radiator, by it self; again, in both directions.

7. When all signs of colour & debri in the water disappear,  reassemble the complete coolant system.

8. Fill the system with clean water, & make sure there are no air locks left in the system.

9. Get hold a good coolant passage "cleaner additive" & add to the coolant, & drive car for a week or upto 1000 klms.

10. Remove hoses & drain & flush again.  

11. If the coolant system corrosion is very bad, then you might have to repeat 4-10 again for another week.

12. When the system is nice & clean, add a high performance, high temperature coolant liquid, & it should be good for a number of years.

After doing this exercise, be aware there is always the possibility of welch plugs breaking through, where heavy rust on the rear (where you can't see it) has been diminished by the chemical cleaning process.  It is important, when doing this exercise, that hoses are removed,  The regular drain holes in the bottom of the radiator, & the front of the block, are too small to allow all the larger bits of crud that get released, to pass out of the system.

P.S.  If the system is very badly corroded, then remove water pump & have a look inside.  If it is very bad, or there is noticeable movement or noise from its bearing, then replace water pump.

Sounds like a lot of mucking around, but if done properly, your engine will love you.

Cheers Banjo   

 

 

Edited by Banjo

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Yes, the gasket blocks front holes that are matching in the block & head, letting a very small flow through until it reaches the back cylinders. I have wondered if Toyota made a design mistake with the casting and covered the overheating rear cyls with the gasket.

There are so many tings in a car that make we wonder 'why did they do this?'....      but sadly no-one to ask!

block.jpeg

gasket.jpeg

Head.jpeg

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Thanks a lot for all the great information! You guys are awesome! Excited to learn all these things and put a wrench to my Corolla. 

Check out my video though! I've uploaded 2 videos so far. Hope you guys like it!

https://youtu.be/EhR7Hjyi8jI

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