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thermostat housing bolts on to?

1492 Views 5 Replies 4 Participants Last post by  Corrolla clone
Hello Folks,

I want to do a coolant flush on my 91 corolla dx with 39,000 miles on it. I did it at 20,000 miles 10 years ago. I need to know the name of the part that the thermostat housing bolts on to. This part also has a heater hose, one more smaller hose, a bypass hose possibly?), & (I believe) the coolant temp sensor. I noticed some type of build up where the hoses clamp to this part which basically is located between the thermostat housing & the engine head. I would like to remove it & clean it or replace it if necessary. I assume it will be a dealer item so I need to know what to ask for if I have to buy one. Anyone ever buy this?

I am currently driving this car approxamitely 150 miles per week plus a 700 mile trip every 4 months on average. I want to replace ALL the hoses. I don't want any surprises so I'd rather be pro-active. Also, any coolant recommendations? The owners manual says to use ethylene-glycol coolant with no alcohol.

Thanks.:D
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Well wouldnt that be the actual thermostat housing?

As for coolant, green stuff will do.
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Well wouldnt that be the actual thermostat housing?
Well, yes and no. According to Toyota there is the 'water outlet housing'and the 'water inlet housing' on a Corolla VI and thogether these comprise what most of us call the 'thermostat housing'.

The thermostat can be accessed and removed by only taking off the 'water inlet housing' (the 'water outlet housing may be left in situ).

Based upon their description of the component, I would suppose that 1991 Toyrolla thinks the 'water inlet housing' is the thermostat housing and wants to know the name of the 'water outlet housing'.
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Well, yes and no. According to Toyota there is the 'water outlet housing'and the 'water inlet housing' on a Corolla VI and thogether these comprise what most of us call the 'thermostat housing'.

The thermostat can be accessed and removed by only taking off the 'water inlet housing' (the 'water outlet housing may be left in situ).

Based upon their description of the component, I would suppose that 1991 Toyrolla thinks the 'water inlet housing' is the thermostat housing and wants to know the name of the 'water outlet housing'.
Don't feel too bad, as I've run into this a lot being that I've been working on American cars most of my life. It seems the Japanese have to re-name everything, and I've had to relearn a bunch of common items over the years.
In the case you're dealing with, the "inlet" is probably the side that actually holds the T-stat (from the water pump). The "outlet" side has the hose that goes to the radiator. I don't know for sure if this is how it's called out or not. Just make sure you put the air bleed hole up or at the 10 o'clock position so it'll allow the air to bleed out of the cooling system.

You really should get a FSM (Factory Service Manual) if you're going to start doing your own repair work, as it'll pay for itself quickly. You could also look in it to see which part is which, as it'll be called out by the "correct" names in it. I got my Toyota Corolla FSM) off e-bay for 20 bucks, and my Geo service manual for 6 bucks shipped. Both cars are very similar, but I wanted the Geo book for the wiring diagram, as it uses some GM stuff in it, versus Toyota stuff (the car is a joint combo of parts). I hope this helps, and good luck with your project. Let us know the end result, as we like to hear about success stories. ;)
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Don't feel too bad, as I've run into this a lot being that I've been working on American cars most of my life. It seems the Japanese have to re-name everything, and I've had to relearn a bunch of common items over the years.
In the case you're dealing with, the "inlet" is probably the side that actually holds the T-stat (from the water pump). The "outlet" side has the hose that goes to the radiator. I don't know for sure if this is how it's called out or not. Just make sure you put the air bleed hole up or at the 10 o'clock position so it'll allow the air to bleed out of the cooling system.

You really should get a FSM (Factory Service Manual) if you're going to start doing your own repair work, as it'll pay for itself quickly. You could also look in it to see which part is which, as it'll be called out by the "correct" names in it. I got my Toyota Corolla FSM) off e-bay for 20 bucks, and my Geo service manual for 6 bucks shipped. Both cars are very similar, but I wanted the Geo book for the wiring diagram, as it uses some GM stuff in it, versus Toyota stuff (the car is a joint combo of parts). I hope this helps, and good luck with your project. Let us know the end result, as we like to hear about success stories. ;)
I don't feel bad at all.

Thanks for the tips. I've been doing repairs on vehicles for around 40 years - bottom end rebuilds, top end rebuilds, bodywork etc, etc. I have amassed a library of workshop manuals.

Like anyone with internet access, I also have access to the full Toyota parts database (exploded diagrams, part numbers, part substitutions, etc, etc) that tells me what the official part name is for every part in every Toyota vehicle made in the last 50 years. You should check it out, it's useful.

Over the years I have realised that terms vary by time, country and manufacturer. When someone asks what a part is called I try to be helpful, I endeavour to tell them what their particular manufacturer calls it and then explain any generic term that might also be used locally. In the case of the 'thermostat housing', for the Corolla VI this is widely known as the 'water outlet' and 'water inlet' in the UK, but in New Zealand it can be called the 'water outlet' and 'water inlet', or the 'thermostat housing' or the 'coolant junction assembly'.

But hey ho,

"You say air bleed hole and I say jiggle pin,
You say FSM and I say workshop manual
bleed hole, jiggle pin FSM, workshop manual
Let’s call the whole thing off."

You should Google 'Holden Nova', I think you'll find the Wiki comments about GM's contribution to the Holden-Toyota alliance interesting.

BTW, what project?
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I don't feel bad at all.

Thanks for the tips. I've been doing repairs on vehicles for around 40 years - bottom end rebuilds, top end rebuilds, bodywork etc, etc. I have amassed a library of workshop manuals.

Like anyone with internet access, I also have access to the full Toyota parts database (exploded diagrams, part numbers, part substitutions, etc, etc) that tells me what the official part name is for every part in every Toyota vehicle made in the last 50 years. You should check it out, it's useful.

Over the years I have realised that terms vary by time, country and manufacturer. When someone asks what a part is called I try to be helpful, I endeavour to tell them what their particular manufacturer calls it and then explain any generic term that might also be used locally. In the case of the 'thermostat housing', for the Corolla VI this is widely known as the 'water outlet' and 'water inlet' in the UK, but in New Zealand it can be called the 'water outlet' and 'water inlet', or the 'thermostat housing' or the 'coolant junction assembly'.

But hey ho,

"You say air bleed hole and I say jiggle pin,
You say FSM and I say workshop manual
bleed hole, jiggle pin FSM, workshop manual
Let’s call the whole thing off."

You should Google 'Holden Nova', I think you'll find the Wiki comments about GM's contribution to the Holden-Toyota alliance interesting.

BTW, what project?
Same here, been doing my own work for 40 years myself.
Your car, your project.
I think I'll pass on the Toyota-Holden connection, as my Geo Prizm was assembled in California at the Nummi plant that now builds Tesla's. GM's contribution wasn't much though, maybe the radio and seat material, along with the dash layout (switch locations) and sheet metal styling being some of the main differences. Where the Corolla got an extra window in the rear door, the Prizm got an extra window behind the door.

I only mentioned the air bleed hole, as I've also worked on a few Honda's in the last 6 or 7 years, and they use 1 as well. I've never seen a pin in that area, but I have seen a hole there.
Kind of like using a "torch" to look inside a fuel tank. Over here we use a "flashlight" to do that. ;) I only bring that up, as I also work on air cooled VW's, and belong to several groups which include members from the UK, Aus, Canada, and other countries besides the USA. And we have to work around the language barrier, as countries have different names for different items.
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