Water Under Min When The Car Is Cold

[Zdeno]

Hello, I would like to ask you guys. I have 1991 LS 400 and when the car is cold (after night in the morning) the water is 1 inch under minimum in the water tank, but when the car getting hot the water come up and it is around MAX. IS it normal ??? thank you

[SKperformance]

It can mean the rad cap needs replacing or there is air in the system.

It is prettty normal to move up and down. If it overflows or drains out then you have a problem.

[wwest]

The proper water anti-freeze/coolant mixturre ratio shouldn't do this. But it doesn't hurt to top it off so the "hot" measure is a bit high but not to the point of overflow. Nothing to worry about as long as "hot" measure is reasonably close, certainly never below "cold" measure.

[VMF]

flush the system its not coz of the cooling but you have air in the system. and air volume is increasing when its getting hot thus making it look like the system is full. so you just flush it completely and fill it with the mix of water and red coolant. make sure you use red coolant.

[Zdeno]

Thank you very much guys !!!

[BlackLex]

<_<

Complete flush , is there a easy way I can do this? Myself?

[Zdeno]

I didn´t flush it yet so I don´t know if I can do it by myself. But I think that the better way will be when I will go to Jiffy Lube, or to Good year I found coupon there for $ 29 in Penny saver but I don´t know if I can trust them.

[Zdeno]

Hi guys, I really need a help. I have been in JIFFY lube and the guy from there told me that there is no place where the air can be and that I have clean coolent so the problem isn´t air in cooling system. If I have air in cooling system I can figure out it when I open reservior and leave the engine turned on for 10 minutes. Today I was meeting my friend, he is volvo machanic, he doens´t know anything about Lexus, but he said to me - I don´t want to scare you, but it can be gasket under the haed. The air from engine can come to water and it can cause that the level coming up when the car getting to higt rpm after little drive. I don´t know how to know where is the problem if the guy from Jiffy lube is right, so it is not air or if my friends guess is good (I HOPE NOT !). Or if it can be thermostat. The car doesn´t overheat ! Works normal. I don´t have any idea

[99lsguy]

Unscrew your oil cap and turn it over. If you see that the oil is 'MILKY' looking up in the oil cap then that is a sign the head gasket may be cracked/leaking. If it is just the color of your oil - I'd say the head gasket is OK.

[Zdeno]

Yes I checked the oil and it is fine. There is no ´MILKY´. Is it possible that the air can come to water but not water to engine ??

[Zdeno]

I don´t know when the head gaket is bad the water should be in engine too but the oil is clean. So the air has to come just to one way - to cooling system. Is it possible ?? When the car go to hight rpm the level go hight too. I appreciate any ideas, thaks

[99lsguy]

Maybe there's a crack in the coolant reservoir. UP high around the top rim or in the cap area. If it were low I imagine you'd see coolant leaking, seeping, etc.

Perhaps the radiator cap is faulty?

Just more ideas...

[Zdeno]

Thank you for ideas, now I´m so afraid. I remember that my friend from volvo asked me if the hose from radiator to engine ( i meant the big hose ) is hard and inflation so I checked the hose after while driving and I have to tell that the hose is very hard and seems inflation. :-(

[Zdeno]

and the coolant reservoir I had to replace month ago, because there was crack.

[Lextech2k3]

ok the one thing that everyone is missing here is that when fluid gets hot it expands...hence the reason for the min/max lines....the true test to see if you have any air is to take loose the 14mm or 10mm alen bolt at the top of your thermostat housing....that is the point that the block bleeds the air from when you flush the coolant system....chances are that if there is any air at all in the system it's there. Btw on an ls the top hose gets hard because it's feeding the thermostat which is usually mostly closed...especialy at idle. you probably don't have a problem at all if your car is not running hot...i'd just say to top the coolant off and be done with it...btw make sure you use the same color coolant that you have in it when you top it off....or else you will have some major problems....

P.S. if you want to know if you have a blown head gasket check to see if the car makes thick white smoke at startup that smells sort of sweet...(note: obviously if it's cold out when you start your car it will make white smoke anyway cause of the steam it creates...but it will not smell).

[Zdeno]

THank you very much !!! You know one month ago I fill the reservoir with another coolant then was inside I guess. I don´t know what kind of coolant the mechanic put in when he changed the reservoir and then I filled with some what I had at home. May I try the alen bolt when the car is hot ?? I meant right NOW ?? And what do you think about big hose from radiator ? Is it normal when is so hard and iflation ?? Thank you very much !!!!

[99lsguy]

Zdeno,

Toyota Long Life Coolant (red) is what you want to use - it's probably not good to mix.

I think under normal pressure the hose shouldn't be rock hard. You should be able to "squeeze" it in a little bit even if its hot. If this hose is really 12+ years old it may be ready to give out. My advice would be go get a new one.

Instructions for my 99 LS is to fill the engine coolant thru this plug on top of the T-stat / Throttle body area. Lexus wants you to fill it this way to minimize air. After fill, turn heat on HIght for a few minutes. Stop engine and top off in reservoir.

I'd let the engine cool a little (I think) to let some pressure off. Be careful not to get burned. Find a replacement hose and visually compare it to what's in the engine now. If you see a difference, - old one is more swollen - get the new one on there.

Good Luck & be careful---> if the coolant is hot & under pressure -- Wait!!

[Zdeno]

Thank you !!! I already fill it when the car was cold. I fill it between MIN and MAX but after while driving the coolant went up and up 2 mm under cup I think when I should drive more the coolant came out under cap. So I will try the replace coolant like you told and I will see. Thank you !!

[Zdeno]

I need the torque wrench to take loose alen bolt at the top of thermostat. I couldn´t do that with regular wrench :-( So tomorrow

[VBdenny]

After talking to Curt Oberg about the coolant reservior fluctuations, I believe it is fairly common for the level to be quite low when cold, and up to, or over MAX when hot. Personally, I think the tanks were made a little small, and mislabeled. Everytime I ever filled it to MIN when cold, it ran all out the top and made a mess. I run mine just slightly above the low radiator fluid sensor which puts it slightly above MAX at normal temperature. I haven't noticed any difference in summer or winter.

Since I quit refilling the tank, I haven't had any leakage.

[99lsguy]

Zdeno,

yes - a torque wrench is good thing. The water filler plug (on top of throttle body and near T-stat) is torqued to 33 ft. lbs. The other drain plugs are 9 ft. lbs torque.

Have you gotten a NEW UPPER HOSE? You might as well while the coolant is drained.

Just for reference, on my 99, the coolant level in my reservoir hardly moves at all. The tank is larger that older models, I think. The diff. between the low mark and high mark is only about an inch on the tank.

[Zdeno]

I didn´t change upper hose yet, it is not original and looks new. I have this car just 3 month (btw I just finding so much problems on this car) so I think the hose is changed by original owner but if it will not to be air under the thermostat bolt I will exchange it for sure. Thank you