Remove Replace SP20 Engine & Gearbox

[xgen]

Ok so I need some more advice and here's what I am about to do.

Just bought a 2001 SP20 not long ago that had 190,000km on the clock. It also had receipts for engine works totaling $2,200 - including water pump, new timing blelt and head repair as it had obviously been overheated.

The car ran fine for a few months no problems at all engine has no smoke and purs like a kitten. However, the other day the radiator fluid was boiling in the reservoir. This would indicate that there is an issue somewhere with the cooling. It seems to fill up the reservoir when I stop and then when the engine is cold it empties it again. Had all cylinders checked for compression and they were fine around 190 to 180 although one had 165 but that is not a concern given the km's on the clock. No oil in the water and no water in the oil and no smoke in the exhaust.

However, given that the car is driven all the way to Cooroy every day I got nervious and bought a replacement engine on eBay that comes with a gearbox as well that has only done 87,000km.

So has anyone on here pulled out an SP20 motor and gearbox before that has step by step pictures or something so that I don't make any mistakes and what to do or not to do? How long should I allow? I have the use of my brothers block and tackle plus all his tools.

Also is does anyone want to buy the engine and gearbox that I am taking out that runs perfect except for the cooling problem that might just be the radiator?

[phunkdust]

Service manuals here

http://www.unfinishedsymphony.net/service/

[Rupewrecht]

Didn't try changing the thermostat etc?

[maztech]

PM me with your location and price for the motor and Box ,I will buy it if you want a reasonable price.

[TheMAN]

190-180psi is below normal for this engine, though still within acceptable levels
however, that one cylinder with 165psi isn't... the maximum allowable difference between cylinders is 28psi

also, don't dismiss the fact that radiator caps do go bad over time and a bad one will lead to boil over conditions even though nothing else is wrong.... at the very least replace the cap and see how it goes... they're cheap anyway and it won't hurt to try!

[xgen]

Thankyou so much everyone for your appreciated advice!

[SuperYellowSP20]

So how did it go with replacing the radiator cap and/or themostat? Am curious. Once I had a 4Runner which overheats alot and found that the themostat was broken open. Broken open or stuck open themostats cannot control the water flow through the radiator to give sufficent cooling before it goes back into the engine.

[70NYD]

Originally Posted by SuperYellowSP20

So how did it go with replacing the radiator cap and/or themostat? Am curious. Once I had a 4Runner which overheats alot and found that the themostat was broken open. Broken open or stuck open themostats cannot control the water flow through the radiator to give sufficent cooling before it goes back into the engine.

I thought thermostats stay closed untill the engine warms up to help get to operating temp faster, allowing oil to get to operating range faster reducing wear, not the other way around. Are you sure about your statement there?

[70NYD]

Oh and this sounds like a radiator cap being dodgy and not holding pressure

[SuperYellowSP20]

Yes I am sure of my statement. Yes you are right that themostat stays closed while engine warms up quicker then partly open to have coolant flow through to cool it down, keeping temperature at it should be.

Water flow too fast through the radiator, not giving enough time for it to cool down in radiator can cause overheating.

Other example I noticed with my 4runner, when in very cold morning driving downhill on a freeway at 100kmh, I applied no power from engine. the temperature gor really cold, the needle went right back to the C mark. If themostat is working, it should close again when coolant gets cold so engine can stay warm. U get what I am saying?

So themostat is to help engine warm up quicker and to keep the engine at designed temp range.

[TheMAN]

that's not the primary reason, even though coolant flow and radiator dwell time has a role in this matter, the reason is this:
http://www.are.com.au/feat/techt/thermostat.htm

our engines and many engines made in the past 20 years uses a bottom bypass valve in the thermostat to regulate the coolant flow in the bypass pipes, which is why a wrong thermostat that "fits" (no bottom bypass valve) or no thermostat could cause overheating

[70NYD]

I have ran cars without a thermostat as a temp fix and never over heated. They took forever to get to operating temp but, hence why I never did so for extended periods of time
Water exchanges heat more readily than air, and I don't see how the pump can cause flow SO high to make the radiator inefficient. A thermostat is not exactly a throttling valve for the cooling system (more a on-off valve) I understand how thermostats work so what exactly am I missing here as I don't get how a stuck open thermostat can cause over heating (ESP since the temp gauge wasn't showing hot). A stuck closed yes. But stuck open not. So please explain how a stuck open thermostat will cause over heating.
A stuffed radiator cap can cause boiling in the fluid (as can a stuck closed thermostat, but that would indicate on the dash) and air in cooling system can show a full reservoir when full while low or nothing when empty

[SuperYellowSP20]

Yes it makes sense. I dont mean to cause any trouble. Just that I learnt by myself by judging what happened to my four runner. When i had my cooling system looked at by me and my mate and we found a broken themostat stuck open.. then we got to this concusion that it was the cause of the high flow. I guess I was wrong. Yes i am aware a stuffed radiator cap can cause overheating. So now I am puzzled why my four runner overheated with broken open themo then never overheated again when i just replaced the themo? I am no mechanic wise, i just felt it was the cause.

[SuperYellowSP20]

Then again my fourrunner was a '85 model so maybe it didnt have the bypass valve then?

[70NYD]

dont get me wrong, i wasnt attacking you (although it looks like it when i re read it now )

i really mean what am i missing there?
i know how it works, but i hear this so often that there has to be something behind it

[SuperYellowSP20]

Its cool, I know what ya mean. I really felt it was the themo because the engine stopped overheating when I replaced it. The old themostat's spring was partly broken off (rusty) and the middle plate which blocks the waterflow was on fully open position. Strange. Anyway I was very glad I didnt have to replace the engine or the cooling system that time as i was broke then.

[rodhog]

Originally Posted by TheMAN

our engines and many engines made in the past 20 years uses a bottom bypass valve in the thermostat to regulate the coolant flow in the bypass pipes, which is why a wrong thermostat that "fits" (no bottom bypass valve) or no thermostat could cause overheating

You know they are not fitted to Australian Models.

According to the following workshop manuals - Mx-6/626 GD and GE BA 323 and HD 929. They are shown as fitted in every market But Australia. Diagrams still show it early cars.

I ordered my self from Mazda Australia - Thermostats for both F2's - KL-' KF's
all were single thermostat with no bypass. Still have KF one sitting around

I also ordered from NZ - A Thermostat for a FE DOHC. - Has the twin thermostats is listed to fit both BP -KF KL and FE engines. NZ cars use same as Japan. According ot the NZ boys it's because in Japan and NZ you can get heat shock from cold coolant from forzen temps hitting Hot engine temp fluid. Because We only have a extremelty low locations of areas that will get yearly temps below 10degree C. It's not seen as problem.

Australia No even listed on mazda's parts list.

Note radiator caps go bad constantly.

on Ba 323's V6 inparticular it was common problem with it and Eunos 500's. Mazda never quite got the caps to last. But it was better then having the expantion tank explode or leak like on the GE KL's.

[TheMAN]

Originally Posted by 70NYD

I have ran cars without a thermostat as a temp fix and never over heated. They took forever to get to operating temp but, hence why I never did so for extended periods of time
Water exchanges heat more readily than air, and I don't see how the pump can cause flow SO high to make the radiator inefficient. A thermostat is not exactly a throttling valve for the cooling system (more a on-off valve) I understand how thermostats work so what exactly am I missing here as I don't get how a stuck open thermostat can cause over heating (ESP since the temp gauge wasn't showing hot). A stuck closed yes. But stuck open not. So please explain how a stuck open thermostat will cause over heating.
A stuffed radiator cap can cause boiling in the fluid (as can a stuck closed thermostat, but that would indicate on the dash) and air in cooling system can show a full reservoir when full while low or nothing when empty

cavitation reduces cooling efficiency because of the water moving too fast

[TheMAN]

Originally Posted by rodhog

You know they are not fitted to Australian Models.

According to the following workshop manuals - Mx-6/626 GD and GE BA 323 and HD 929. They are shown as fitted in every market But Australia. Diagrams still show it early cars.

I ordered my self from Mazda Australia - Thermostats for both F2's - KL-' KF's
all were single thermostat with no bypass. Still have KF one sitting around

I also ordered from NZ - A Thermostat for a FE DOHC. - Has the twin thermostats is listed to fit both BP -KF KL and FE engines. NZ cars use same as Japan. According ot the NZ boys it's because in Japan and NZ you can get heat shock from cold coolant from forzen temps hitting Hot engine temp fluid. Because We only have a extremelty low locations of areas that will get yearly temps below 10degree C. It's not seen as problem.

Australia No even listed on mazda's parts list.

Note radiator caps go bad constantly.

on Ba 323's V6 inparticular it was common problem with it and Eunos 500's. Mazda never quite got the caps to last. But it was better then having the expantion tank explode or leak like on the GE KL's.

the GY/K8/KF/KJ/KL/RF thermostats are all the same as the FP/FS
they DO have a bottom bypass valve... I guess you didn't notice?

besides that, I said "many", not all... and since this thread was about the SP20, I fail to see the relevance of mentioning the other Mazdas

the NTCL OEM Mazda one is on the left, the Stant aftermarket low temp one is on the right.. BOTH have the bottom bypass valves as shown in the pic

this particular thermostat is used worldwide and what is used in the US and Japan is also used in Australia

Mazda part number: KL01-15-171A
Stant 76.6 degree low temp part number: 14047 or 35047 or 29047 (blister pack)


here is the WRONG thermostat for the FP/FS/K series engines, which has NO bottom bypass valve:


and another example of a thermostat with the bottom bypass valve.... this one is from the Ford Duratec/Mazda MZR engine:

[70NYD]

Originally Posted by TheMAN

cavitation reduces cooling efficiency because of the water moving too fast

a partially opened thermostat will create more cavitation/restriction than a fully opened one.
as long as the thermostat that is in there is correct size (ie not smaller) the restriction will be same if its fully operational but opened or stuck opened. so i dont see the point of your statement there
i still think the only thing it will do is let your car run cool for longer possibly creating damage due to the oil not heating up properly, and perhaps in very cold climates not allow the engine to heat up properly at all
a bypass valve allows for a more even temperature within the engine as the water is allowed to circulate during initial warmup rather than having hot spots..
i still fail to see how a stuck opened thermostat will cause over heating