possible coolant leak

[RHYSF00]

so i noticed every 3 weeks the line of collant has dropped. i filled coolant back in july to full as garage only half filled it. it has gone back to around half full. i park in same slope when i check fluids and there is no sign on an external leak nor any sign of coolant in oil. i can sometimes smell coolant/ screenwash when i first start caror when i have heatcore on. if anyone can guid me to diagnose the possible leak i be much thankful. please make sure it is simple due to me having asd i find it hard to follow paragraphs.

[Sooty]

If it is only dropping to the same mark it is most likely the pressure relief valve in the radiator cap releasing the excess pressure. 

Just leave the coolant alone and see if it drops lower than you have noticed.

Odds on that it will not drop any further.

[RHYSF00]

7 minutes ago, Sooty said:

If it is only dropping to the same mark it is most likely the pressure relief valve in the radiator cap releasing the excess pressure. 

Just leave the coolant alone and see if it drops lower than you have noticed.

Odds on that it will not drop any further.

the fluid dropping but noticable every 3 weeks. unless im not ment to fill to fill line?? would prestone ready to use coolant be ok?

[fourbanks]

3 minutes ago, RHYSF00 said:

the fluid dropping but noticable every 3 weeks. unless im not ment to fill to fill line?? would prestone ready to use coolant be ok?

prestone is one of the very best, so yes

[APS]

First of all - I'm assuming you are checking the level with the engine always at the same temperature i.e. either hot or cold.

Most often, coolant leaks are external. Slow leaks like such as you describe, are particularly difficult to spot. If you do manage to see the leak you should see light red or blue crusty residue. Two possible things to look for:

INSIDE - heater: You could have a leak in the heater matrix inside the car. The tell tale signs would be a slightly sweet smell, and fog on the inside of the windscreen that is very slow to clear. You could also get soggy carpets. But if the leak was that bad, you'd definitely have very obvious fogging up issues.

ENGINE - water pump: I'm not sure what engine you have in your car, but a likely problem area would be the water pump. Look for spatter around the periphery of the pulley and belt. If the pump leaks you'd get whitish spatter on surrounding components. It may be subtle and not immediately obvious until you look really close.  This kind of leak can be enough reduce the level over a period of months without many streams or pools forming anywhere. 

[oldcodger]

As well as all the above, we have had such leaks on our 1.6, the first was a small leak at the bottom / front of the radiator,  only really spotted once the air con 'radiator' was removed.

The next was from the thermostat housing,  again hard to see because its covered by the alternator and you need a small mirror and strong torch make it easier to spot any signs of dried crusty coolant.

[Rhymes with Paris]

I don't normally recommend any kind of gunk,or bodges, but sometimes can be a short term solution.

But depending on the age of of a car, and how long you intend keeping it, Wynn's coolant stop leak worked for me once.

It was a slow leak on a 92 pug 405 with an aluminium rad, I could not trace the leak and the car was getting on a bit by then.

As the others say maybe not a leak at all, so only a possibility once other causes for coolant level going down are ruled out.

But this stuff in the old pug did stop the leak for at least a year until I sold it, and did not clog the cooling system up.

 

[DerekHa]

Hi Rhys,

would agree with the above, have used Wynn's products in the past and more times than not they have worked. If you can't find any signs of leakage it's likely your only option but try the pressure relief cap like Sooty says first

I've waterpump seal leaks on a couple of engines where the pump body and seal are covered by the timing gear cover on the front of the engine. Never found the actual leak until I removed the cover and saw there was old rusty water splashed all around the inside of the cover, all out of sight. Not sure of your engine layout though.

Was introduced to Wynn's products by a really good old time mechanic years ago, I thought he was mad using an oil treatment on a Rover 800 Sterling with very noisey tappets, after ten minutes the tappet noise stopped and the engine ran perfectly.

[RHYSF00]

6 hours ago, APS said:

First of all - I'm assuming you are checking the level with the engine always at the same temperature i.e. either hot or cold.

Most often, coolant leaks are external. Slow leaks like such as you describe, are particularly difficult to spot. If you do manage to see the leak you should see light red or blue crusty residue. Two possible things to look for:

INSIDE - heater: You could have a leak in the heater matrix inside the car. The tell tale signs would be a slightly sweet smell, and fog on the inside of the windscreen that is very slow to clear. You could also get soggy carpets. But if the leak was that bad, you'd definitely have very obvious fogging up issues.

ENGINE - water pump: I'm not sure what engine you have in your car, but a likely problem area would be the water pump. Look for spatter around the periphery of the pulley and belt. If the pump leaks you'd get whitish spatter on surrounding components. It may be subtle and not immediately obvious until you look really close.  This kind of leak can be enough reduce the level over a period of months without many streams or pools forming anywhere. 

Cold about 9 am. 

[RHYSF00]

3 hours ago, Rhymes with Paris said:

I don't normally recommend any kind of gunk,or bodges, but sometimes can be a short term solution.

But depending on the age of of a car, and how long you intend keeping it, Wynn's coolant stop leak worked for me once.

It was a slow leak on a 92 pug 405 with an aluminium rad, I could not trace the leak and the car was getting on a bit by then.

As the others say maybe not a leak at all, so only a possibility once other causes for coolant level going down are ruled out.

But this stuff in the old pug did stop the leak for at least a year until I sold it, and did not clog the cooling system up.

 

Olan on keeping it as long as possible 

[oldcodger]

You need to inspect the 3 main causes of water loss, the radiator, water pump and thermostat housing; head gasket is possible but quiet unusual on a Corolla as is a leaking heater matrix, but worth checking for a soggly carpet around the footwells.

None of those parts are that expensive if they need replacing, and if is any one of those 3 things then you should be doing a full coolant change at the same time along with a new thermostat and sealing ring.

Pics below show what to look for, though probably with your low coolant loss, you will not see as much dried crud around.

Doing you own repair or using a garage?  if a garage they can do a coolant pressure test which may quickly show where the leak is.

 

[RHYSF00]

48 minutes ago, oldcodger said:

You need to inspect the 3 main causes of water loss, the radiator, water pump and thermostat housing; head gasket is possible but quiet unusual on a Corolla as is a leaking heater matrix, but worth checking for a soggly carpet around the footwells.

None of those parts are that expensive if they need replacing, and if is any one of those 3 things then you should be doing a full coolant change at the same time along with a new thermostat and sealing ring.

Pics below show what to look for, though probably with your low coolant loss, you will not see as much dried crud around.

Doing you own repair or using a garage?  if a garage they can do a coolant pressure test which may quickly show where the leak is.

 

Not seen anything like that

[RHYSF00]

Took some photos

[APS]

Thanks for the photos.

I don't see anything wrong there (I do see your lubricated clutch release cylinder :). All looks fine. 

If the radiator leaks, it will most likely leak at the bottom on the front side. This is hard to get to since the bumper/grille and most likely the AC condenser is in front of it.

You have the 1.4 petrol (4ZZ-FE) where the water pump is part of the timing chain cover. I'm not sure how obvious coolant leaks will be. But you probably need to get underneath the car to see.

Do a Google search for "4ZZ-FE coolant leak" and you should find some photos of common leaks.

[RHYSF00]

1 hour ago, APS said:

Thanks for the photos.

I don't see anything wrong there (I do see your lubricated clutch release cylinder :). All looks fine. 

If the radiator leaks, it will most likely leak at the bottom on the front side. This is hard to get to since the bumper/grille and most likely the AC condenser is in front of it.

You have the 1.4 petrol (4ZZ-FE) where the water pump is part of the timing chain cover. I'm not sure how obvious coolant leaks will be. But you probably need to get underneath the car to see.

Do a Google search for "4ZZ-FE coolant leak" and you should find some photos of common leaks.

ok thanks. one thing i did notice when was taking photos it gained fluid. but when heater core on full speed i can smell a sweet smell around the v belt.

[oldcodger]

You really need a small extendable inspection mirror to view the underside of the water pump or look at it from under the car , probably with the undertray removed.  see pic where the little hand is pointing,

A small leak drop by drop will be dried quiet quicky, so do not expect masses of crud as in those earlier pics.

Same with the themostat housing.

The radiator, more likely to be on the front side, agian removing the undertrays and viewing from underneath may give you a better view.

You can gain partial access to the front by  uncliping  and removing the fan cover, then undo the two top radiator retainers and that should allow you to very carefully  lift it up a fraction, which then allows you to hinge it back from the top towards the engine just enough to see down the front, as said it often goes down at the bottom towards the solid ends.

If you cannot see anything then call in at a couple of local garages for a coolant pressure test or buy your own test kit  ?   ... though never used one.

https://www.amazon.co.uk/DHA-Radiator-Pressure-Aluminum-Adapters/dp/B07YRRSH8F/ref=sr_1_7?keywords=Coolant+Pressure+Tester+Kit&qid=1666792880&qu=eyJxc2MiOiI0LjA5IiwicXNhIjoiMy42NiIsInFzcCI6IjMuNDkifQ%3D%3D&sr=8-7

 

[RHYSF00]

15 minutes ago, oldcodger said:

You really need a small extendable inspection mirror to view the underside of the water pump or look at it from under the car , probably with the undertray removed.  see pic where the little hand is pointing,

A small leak drop by drop will be dried quiet quicky, so do not expect masses of crud as in those earlier pics.

Same with the themostat housing.

The radiator, more likely to be on the front side, agian removing the undertrays and viewing from underneath may give you a better view.

You can gain partial access to the front by  uncliping  and removing the fan cover, then undo the two top radiator retainers and that should allow you to very carefully  lift it up a fraction, which then allows you to hinge it back from the top towards the engine just enough to see down the front, as said it often goes down at the bottom towards the solid ends.

If you cannot see anything then call in at a couple of local garages for a coolant pressure test or buy your own test kit  ?   ... though never used one.

https://www.amazon.co.uk/DHA-Radiator-Pressure-Aluminum-Adapters/dp/B07YRRSH8F/ref=sr_1_7?keywords=Coolant+Pressure+Tester+Kit&qid=1666792880&qu=eyJxc2MiOiI0LjA5IiwicXNhIjoiMy42NiIsInFzcCI6IjMuNDkifQ%3D%3D&sr=8-7

 

do you know what push in clips i am gonna need to revit the under tray and fan cover?? will it be the same clips as the rear bumber

[oldcodger]

If you take them out carefully you should be able to reuse them .

Most of the fasteners are self tapping screws / clips on the main part of the undertrays on our 2006 model,  if I remember correctly.

You can find small packs of similar fasteners at Halfords, The Range etc  that may fit well enough, though we bought a mixed pack from eBay to cover all things.

Might be easier to get one of these little mirrors before going underneath,  we use them , very handy for many things.

 

[RHYSF00]

1 minute ago, oldcodger said:

If you take them out carefully you should be able to reuse them .

Most of the fasteners are self tapping screws / clips on the main part of the undertrays on our 2006 model,  if I remember correctly.

You can find small packs of similar fasteners at Halfords, The Range etc  that may fit well enough, though we bought a mixed pack from ebay to cover all things.

Might be easier to get one of these little mirrors before going underneath,  we use them , very handy for many things.

 

when i took clips off for rear bumper there wearnt reusable. i looked at the drawings. and it seems to be in by 4 scrws and 4 clips. i will look at getting one of those/ pit car on jacks

[DerekHa]

Hi Rhys,

I googled the 4ZZFE engine looking for images of the Cam Chain cover.

I'll post a link which shows different views of the same. As APS states the cam chain cover forms part of the actual water pump body and the pump impelor bolted directly into that cover plate.

Looking at the design it would be possible for a leak to form between the mounting faces of the cam cover and front of the engine block to and you wouldn't see any sign of any coolant as it will all be contained inside the cam chain cover and likely just evaporate in there. Likely thats why you can smell something sweet around the drive belt when you start up.

https://www.totalparts.nl/eng/car-part/R300000D12/cam-chain-cover+toyota+corolla-e12-hatchback-1-4-16v-vvt-i-4zzfe+2001-2002-2003-2004

The cover, when assembled, doesn't have a gasket as such but the mounting faces have to be sealed with a RTV silicone bead applied on the machined faces.

There's a very in depth video showing how to remove the camchain cover etc on youtube. Here's the link.

 

 

[RHYSF00]

8 hours ago, DerekHa said:

Hi Rhys,

I googled the 4ZZFE engine looking for images of the Cam Chain cover.

I'll post a link which shows different views of the same. As APS states the cam chain cover forms part of the actual water pump body and the pump impelor bolted directly into that cover plate.

Looking at the design it would be possible for a leak to form between the mounting faces of the cam cover and front of the engine block to and you wouldn't see any sign of any coolant as it will all be contained inside the cam chain cover and likely just evaporate in there. Likely thats why you can smell something sweet around the drive belt when you start up.

https://www.totalparts.nl/eng/car-part/R300000D12/cam-chain-cover+toyota+corolla-e12-hatchback-1-4-16v-vvt-i-4zzfe+2001-2002-2003-2004

The cover, when assembled, doesn't have a gasket as such but the mounting faces have to be sealed with a RTV silicone bead applied on the machined faces.

There's a very in depth video showing how to remove the camchain cover etc on youtube. Here's the link.

 

 

Would leak sealer solve it

[RHYSF00]

9 hours ago, DerekHa said:

Hi Rhys,

I googled the 4ZZFE engine looking for images of the Cam Chain cover.

I'll post a link which shows different views of the same. As APS states the cam chain cover forms part of the actual water pump body and the pump impelor bolted directly into that cover plate.

Looking at the design it would be possible for a leak to form between the mounting faces of the cam cover and front of the engine block to and you wouldn't see any sign of any coolant as it will all be contained inside the cam chain cover and likely just evaporate in there. Likely thats why you can smell something sweet around the drive belt when you start up.

https://www.totalparts.nl/eng/car-part/R300000D12/cam-chain-cover+toyota+corolla-e12-hatchback-1-4-16v-vvt-i-4zzfe+2001-2002-2003-2004

The cover, when assembled, doesn't have a gasket as such but the mounting faces have to be sealed with a RTV silicone bead applied on the machined faces.

There's a very in depth video showing how to remove the camchain cover etc on youtube. Here's the link.

 

 

just wacthed the video. that does seem like a big job

 

[DerekHa]

Hi Rhys,

Given the age of that engine I'd be inclined to give the Wynn's leak sealer a try especially as you can't identify where your coolant is being lost.

I had a 1999 1.3 Corolla years ago but don't recall how good the access is to the cam chain cover but would think it's possible to remove it insitu but like you say it's not exactly a straightforward job even having the engine out of the car. Try and take a look under the front end of the engine and see if there's any sign of coolant seeping down the face of the cam chain cover (below the water pump) or between the bottom mating faces of the chain cover and the engine block.

One other thing comes to mind. I've seen the lightwieght castings now used for things such as water pump bodies, thermostat housings etc eaten away internally by water attacking the alloys used, caused by people NOT using coolant, inhibitor or antifreeze. If this is the case, without dismantling all of the cooling system you'll be hard pushed to find that until the casting finally fails/breaks.

Think the leak sealer is your best option given everything. Haven't used any in a very long time but I'm sure that most products can be but into the system and left in there without causing  problems.

[RHYSF00]

1 minute ago, DerekHa said:

Hi Rhys,

Given the age of that engine I'd be inclined to give the Wynn's leak sealer a try especially as you can't identify where your coolant is being lost.

I had a 1999 1.3 Corolla years ago but don't recall how good the access is to the cam chain cover but would think it's possible to remove it insitu but like you say it's not exactly a straightforward job even having the engine out of the car. Try and take a look under the front end of the engine and see if there's any sign of coolant seeping down the face of the cam chain cover (below the water pump) or between the bottom mating faces of the chain cover and the engine block.

One other thing comes to mind. I've seen the lightwieght castings now used for things such as water pump bodies, thermostat housings etc eaten away internally by water attacking the alloys used, caused by people NOT using coolant, inhibitor or antifreeze. If this is the case, without dismantling all of the cooling system you'll be hard pushed to find that until the casting finally fails/breaks.

Think the leak sealer is your best option given everything. Haven't used any in a very long time but I'm sure that most products can be but into the system and left in there without causing  problems.

can confrim it is a 50 50 ratio as i done it myself. will try and get some on order tomorrow. would anyone recommand an engine flush??

[DerekHa]

Have just had a close up look at the cam chain cover for sale I linked for you and hadn't noticed before but:-

Even that cover looks as though it's been attacked around the mating faces closest to the water pump housing, looks pitted and eroded to my eye there but elsewhere all the metal looks good. It's likely a common failure point on that area of the chain cover looking at that one.