Loosing Coolant Big Time!

[ssls400]

have a 92 ls400 and lately i am loosing coolant for the past 2 weeks,i have checked the oil its fine no mayonaise colour in oil filler cap,cant see any hairline cracks on the expansion tank,the sensor is fine and shows no signs of wear,the coolant pipes are all on properly again cant see any splits,there is no puddle under the engine,i can fill the water up to the correct level on the expansion tank and drive as normal by the time tomorrow comes and i check it again i have lost a fair bit of coolant when the engine is hot i check for leaks and underneath, there is nothing to see, so where is the water going?everything was fine a couple weeks ago never had to fill the expansion up.then this starts.please can someone help!!!!!

[Steve_D]

Maybe take it to a garage, they can do a pressure test on the cooling system and have a good look around underneath - if there's nothing visible then maybe a cylinder head gasket leak?

[johnboy]

Are you getting any whitish/grey smoke from the exhaust ?

Just because the oil isnt milky, doesnt mean a headgasket hasnt gone.

[terry moore]

have a 92 ls400 and lately i am loosing coolant for the past 2 weeks,i have checked the oil its fine no mayonaise colour in oil filler cap,cant see any hairline cracks on the expansion tank,the sensor is fine and shows no signs of wear,the coolant pipes are all on properly again cant see any splits,there is no puddle under the engine,i can fill the water up to the correct level on the expansion tank and drive as normal by the time tomorrow comes and i check it again i have lost a fair bit of coolant when the engine is hot i check for leaks and underneath, there is nothing to see, so where is the water going?everything was fine a couple weeks ago never had to fill the expansion up.then this starts.please can someone help!!!!!

HI, check under the front carpets,it could be your heater system. B)

[ssls400]

i have checked all the carpets and they are dry, i have rev'd the engine up and there is no smoking at all of any sorts.

[Haylands]

i have checked all the carpets and they are dry, i have rev'd the engine up and there is no smoking at all of any sorts.

Let it warm up fully, a good 20mins then just let it sit and idle, a good indication of cylinderhead gasket failure is if there is steam coming from the exhaust at tickover not revving it up. If nothing then as said earlier, get it pressure tested at a garage, very simple and pretty cheap

Good Luck

Pete

[bazgtr]

Have you for any reason had a recent coolent If so then the system has not been bleed properly and you have an air lock and the water is burning away. If this was done then you need to do the full instructions(Found on a sticker inside the engine bay to the right, [i have a picture if that helps]). If you don't do this then it will loose coolent. You may also check if you have any coolent in the system as too much water will also evaporate when hot.

If none of the above then check two things.

First is to check under the oil cap to see if there is any white foam bubbles etc. Also look down into the block to see inside for any white stuff. If this is all oily looking then it's not the head gasket. These engine are soild and don't really suffer from this.

Know what I will say is you have a leak around the water pump if your coolent level and content is OK. You need to get a bright touch and shine a light through the gap in between the rotar arm covers and to find the water pump and from below lookling for any water staining. You will need to get the car warm and have a look before the engine cools and everoprates any sign of the leek.

If you have to replace the water pump then do the timing belt aswell while there. I charge £500 for the timing belt and water pump change at the same time. I take 12hours to do this to make sure it's done correctly and have chance to look at other things in that area(Power steering leak etc) for full reliability of the car when it leaves. You can do it in 6-8hours but you get a rushed job and mistakes can happen.

[ssls400]

Have you for any reason had a recent coolent If so then the system has not been bleed properly and you have an air lock and the water is burning away. If this was done then you need to do the full instructions(Found on a sticker inside the engine bay to the right, [i have a picture if that helps]). If you don't do this then it will loose coolent. You may also check if you have any coolent in the system as too much water will also evaporate when hot.

If none of the above then check two things.

First is to check under the oil cap to see if there is any white foam bubbles etc. Also look down into the block to see inside for any white stuff. If this is all oily looking then it's not the head gasket. These engine are soild and don't really suffer from this.

Know what I will say is you have a leak around the water pump if your coolent level and content is OK. You need to get a bright touch and shine a light through the gap in between the rotar arm covers and to find the water pump and from below lookling for any water staining. You will need to get the car warm and have a look before the engine cools and everoprates any sign of the leek.

If you have to replace the water pump then do the timing belt aswell while there. I charge £500 for the timing belt and water pump change at the same time. I take 12hours to do this to make sure it's done correctly and have chance to look at other things in that area(Power steering leak etc) for full reliability of the car when it leaves. You can do it in 6-8hours but you get a rushed job and mistakes can happen.

hi thanks for the fantastic info,i recently put in a brand new thermostat about 3 or 4 weeks ago.i bled it by letting the engine get hot and released the nut on top of the thermostat housing.please can you give me info on the correct procedre for bleeding as i dont have the sticker inside the engine bay

thanks, may also take you up on the offer over the timing belp and water pump later on this year.

[johnboy]

Does the heater get hot ? if not then theres an air lock, and needs bleeding

[nereus4951]

Does the heater get hot ? if not then theres an air lock, and needs bleeding

hi,yes if anything the heater is brilliant bloody hot in about 4 mins or so.

[ssls400]

Does the heater get hot ? if not then theres an air lock, and needs bleeding

hi,yes the heater gets very hot in about 4 or 5 mins something like that

[bazgtr]

Does the heater get hot ? if not then theres an air lock, and needs bleeding

hi,yes the heater gets very hot in about 4 or 5 mins something like that

Guessed as much. After replacing the themosat it's just a case of you not bleeding the V8 correctly and just have a air lock. Once you do this and top up the level you should be OK after that.

PM me your email or send a email to me at barrie.gittins@ntlworld.com and I'll send you a picture of the correct way to do it.

I would forget any other advice in this thread for know until you do this first to make sure. Don't worry loads of people I know with LS400's have done this at some point while working on the car.

[bombs]

Same problem we have but yes I take it to a garage, they do a pressure test on the cooling system and then they found out my cylinder head gasket had a leak.

[lozzysorion]

im also having this problem in mine i seemed to using quite a bit of oil too but no visible smoking i have used 5ls of oil in 5 months

i do do about 2500 miles per month in the car

where is the bleed valve and proceedure located ?