Tips for locating coolant leak?

Catbrain · Sep 3, 2016

Car is 2001 2L 4WD Petrol, Manual GX VVTi

It must be coming out of somewhere as there's a pool on the floor since topping up and running engine, but can't see exactly where... topped up white coolant tank as it was empty after I noticed steam coming from passenger side of engine bay in traffic. Then realised the rad needed topping so did that too... Neighbour thinks it might have just had air in system and so was forcing out coolant as it had nowhere to go. Does this happen? I can see white crust in engine bay where its hit the fan and sprayed everywhere and also along the panels underneath rad, but no idea how long that's been there.

Worried as not sure how long its been dry... Hoping head gasket ok! -how do I make sure of that? Can't see water in the oil or anything like that and car is running like there's nothing wrong.
Had car for a couple months and prior to this was stood for 1 year, so was thinking a perished hose somewhere but all the ones I can see seem ok?

Any tips people? -beware I am very novice! (but I do try my best)

TIA
Cat

Blogson · Sep 3, 2016

Welcome, Cat! This forum is primarily North America-based, so RAV models may differ. We do have some members in the UK and Europe. There can be air in the cooling system but that is unusual unless the coolant has been very recently drained and replaced. If the coolant is pink in color that could make finding a leak easier. S. From your description of the residue in the engine bay there could be a leak from the engine coolant pump, but if so that should be tinged pink in color if the engine coolant is Toyota pink. You've already checked the hoses and for coolant in the engine oil - did you check the engine oil immediately after running the engine? That is the best time to check since if there is coolant in the oil it could separate out when the engine is cold and sink to the bottom of the sump and then would not show so readily on the oil dip stick. Sometimes when I've checked for coolant leaks I've had to remove any plastic pan under the engine and place paper under the engine and cooling system to try to identify where the leak is occurring. Also, have you noted whether the coolant temperature gauge remains in the Normal range? - some people don't pay any attention to their gauge and that can result in engine damage. Good luck, and keep us updated!

Rav450 · Sep 3, 2016

Also check the condition of the radiator cap and thermostat.

Catbrain · Sep 4, 2016

Thanks people!

I'm just about to go and do a bit more exploratory work on it now... Took it around the block and then a little further and nothing came out... but then drove back (stopping to check very regularly) and the level in the white tank had reduced by around an inch upon my return home. I think its doing it when it gets hot enough for the fan to cut in? Am going to check pump and thermostat etc (once i've found them -I really am a novice haha, am glad it still has the manual with it) ... and double check the hoses as really hope its something simple!! :/

I'm used to keeping a close eye on the engine temp gauge -had an old Peugeot before this and not surprisingly it had everything wrong with it in the end!

The Rav never reads as overheating..

At the moment i've just been topping up with water as wanted to ascertain the problem and fix it rather than pay for coolant that keeps falling out of it! :/

Did check oil stick when warm but will do all checks again in relation to all advice above.

Cap on the rad looks good and solid and no residue on oil cap etc which is always nice!

Thanks

Blogson · Sep 4, 2016

Cat, are you filling the reservoir (white tank) to the top or to the Full mark and/or when the engine is at normal operating temperature? Ordinarily coolant level should be checked when the engine is cold - the coolant level should then be at the Low mark. If it is filled beyond that mark when the engine is cold the coolant will expand when it gets to near the normal engine operating temperature and coolant will be blown out of the reservoir. Since it seems that you are refilling the reservoir when the engine is at normal temperature it would appear that may be what is taking place. The blown out coolant could be running down onto the fan and being sprayed around that part of the engine, radiator, etc., and if that all is taking place then you most likely don't have a leak, but are simply overfilling the coolant tank. If that is not the cause for the problem I would suspect that there may be a leak at the coolant pump shaft seal, also because of your description of spray in the radiator cooling fan. Please post back with results.

P.S. - And I know about Peugeots in the UK - have helped a couple of people solve problems which never should have occurred! :wink

Rav450 · Sep 4, 2016

If you can't find the leak visually and by feeling for wetness, you may want to try this method. After a drive, park the car with the engine off place newspaper under the various parts of the cooling system, e.g. coolant tank, radiator, water pump, etc. Hopefully, dampness on one of the sheets of newspaper will isolate the location so a more detailed inspection can be done.

As a side note the radiator cap may look sound but the spring may have lost it's strength.

marbillw · Sep 4, 2016

I noticed you said you had a pool on the floor, where was it located ? Was it on the passenger side ? if it was there, the heater core is usually located there . It could be the heater core if it shows up with the heater on. Of Course if you ment on the garage floor, forget this advice !

Catbrain · Sep 5, 2016

Blogson said:
Cat, are you filling the reservoir (white tank) to the top or to the Full mark and/or when the engine is at normal operating temperature? Ordinarily coolant level should be checked when the engine is cold - the coolant level should then be at the Low mark. If it is filled beyond that mark when the engine is cold the coolant will expand when it gets to near the normal engine operating temperature and coolant will be blown out of the reservoir. Since it seems that you are refilling the reservoir when the engine is at normal temperature it would appear that may be what is taking place. The blown out coolant could be running down onto the fan and being sprayed around that part of the engine, radiator, etc., and if that all is taking place then you most likely don't have a leak, but are simply overfilling the coolant tank. If that is not the cause for the problem I would suspect that there may be a leak at the coolant pump shaft seal, also because of your description of spray in the radiator cooling fan. Please post back with results.

P.S. - And I know about Peugeots in the UK - have helped a couple of people solve problems which never should have occurred! :wink

Hmmm...possibly a rookie mistake there then! When I first noticed steam and pulled over the white tank was completely empty (to my understanding that is when the tank should be more on the full side? like an expansion tank on a radiator?) So I waited for it to cool and filled to top level (I'm sure the manual said that but I might have been reading what I thought it should say?) since then the level has dropped around an inch and a half and puddles the floor around when fans kick in. Properly dripping from somewhere. So it might be in that case that i've stupidly overfilled him? but he was deffo empty when hot before I did anything to it.

cleaned bay off a bit and deffo at the bottom of bay on passenger side (UK) there is water running as it was freshly stained after running til hot. it's hard to find a flat piece of ground to test it on properly -yesterday was leaning towards driver side (UK) and so running out that side.... argh!

I've got another RAV of the same year (don't ask but we made a bad purchasing decision and ended up with a lemon!) with a rad and cooling system that wasn't leaking (the only thing that didn't seem to be wrong with it in the end if i'm honest, it drank oil like petrol and threw it out the exhaust!) so could get my brother to help me swap some bits over in any case... I still can't find the coolant pump? Is it next to/in amongst the belt on drivers side?

Just drove to work (stopping regularly to check everything) and the level hasn't changed on the white tank...

Rookies like me must be so frustrating haha!

Catbrain · Sep 5, 2016

marbillw said:
I noticed you said you had a pool on the floor, where was it located ? Was it on the passenger side ? if it was there, the heater core is usually located there . It could be the heater core if it shows up with the heater on. Of Course if you ment on the garage floor, forget this advice !

Hmm I think it is on the passenger side (UK) but hard to tell as it was dripping and dropping down to the drivers side as my road is sloping quite a but... :roll:

Ran the heater -as a neighbour suggested that, but makes no difference. Seems to leak when fans need to cut in.
Behaved all the way to work. Hmm....

Catbrain · Sep 5, 2016

Rav450 said:
If you can't find the leak visually and by feeling for wetness, you may want to try this method. After a drive, park the car with the engine off place newspaper under the various parts of the cooling system, e.g. coolant tank, radiator, water pump, etc. Hopefully, dampness on one of the sheets of newspaper will isolate the location so a more detailed inspection can be done.

As a side note the radiator cap may look sound but the spring may have lost it's strength.

Might get a new cap then to be sure, but can't see any sign of it coming from there.
I need to remove that plastic trim underneath as things just run along there and drip in all directions. Worried I will take it off and not be able to get it back on again... :/

Blogson · Sep 5, 2016

Since the white tank was empty when the engine was at operating temperature, overfilling as you have discovered is not the source of the leak..The water (coolant) pump is on the engine where the rubber-type belt is and is driven by a/the belt. Am not certain about the second generation RAV but will be in the same area as the alternator and should have a pipe or hose attached for the coolant to run through with the other end of the pipe or hose ultimately going to the radiator. Also everyone working with vehicles for only a short time is a 'rookie' - one has to begin somewhere! Am not certain whether you are still having a coolant leak. If it is and it is not coming from the water (coolant) pump, as in Post #2 you will as you noted have to remove the plastic pan under the engine and cooling system so that you can spread out paper underneath and observe where the coolant is dripping from. To be reasonably accurate your RAV will need to be parked in a level area - do you have a garage? Good luck, and keep posting results. :wink

MNRAV4 · Sep 7, 2016

you should do a cylinder pressure check to rule out a head gasket leak to one or more of the cylinders
the less obvious:
I had a head gasket leak, the affected cylinder clearly ran a different temp, although the spark plug was not significantly different color in mine, it may be in yours. The usual cylinder affected is one of the middle two. The head color was clearly different in the affected cylinder once I got it off.

When it happened to me I could not find a leak, I could only detect a light vapor coming from the passenger side that was only visible in January, once it got warmer, the mist was not observable. It took me several months to figure it out for sure, which could have been found out right away if I had done a compression check (did not have the needed tool although I could have rented it)

After getting the head off I discovered that there was only a minor breakdown in the water jacket to outside (which accountede for the vapor), the main break was to the cylinder and therefore never saw a leak

Tips for locating coolant leak?

Catbrain

Blogson

Rav450

Catbrain

Blogson

Rav450

marbillw

Catbrain

Catbrain

Catbrain

Blogson

MNRAV4

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