81corolla

I don't want sound like a hypochondriac... but I'll bounce this off you guys.

On my 2000 RX300, at the 60K service I had the coolant flushed and refilled. Now, 12K later (18 months) the coolant reservoir level is right at the low mark (engine cold). So clearly the coolant has gone down some since the refill.

I've owned the car for only 2 years so I'm not familiar with it's behavior w.r.t. coolant. On my old Toyota, I'd top off the coolant every once in a while, but I was using the green stuff, not this new fangled pink stuff. :-)

Should I be concerned about a worn head gasket or is this just normal? Should I go to the dealer and ask for a compression test (to document the [potential] problem.) Or should I just go buy some more coolant and top it off?

I've had no thermostat problems whatsoever - car warms up and needle is at half-way point (not like Lexmex's on the track. :-)

Thoughts?

Lexmex

LOL Actually, on the highway it goes sub half-way point.

In regard to your question, from my experience there is coolant loss over the course of the year. Just like oil or any other fluid, the qualities that make these fluids work degrades over time. Even water will burn off after a while.

Granted, I do know people with vehicles where they won't change it for 3 years and still at the same level.

At high altitude where I live, this effect is magnified and I always see loss now after 3 months. I have tried it with both 50/50 water/coolant 30/70 water coolant only 100% coolant with Redline WaterWetter eases the issue.

I change mine out ever year (coming up soon so I will post photos) and top off over the months.

However, for sea level 50/50 water coolant unless you are using the pink stuff.

Tammy

This is normal; I cannot explain why it does it.

Mine fluctuates about an inch and a half to two inches between cold and hot, depending on summer or winter.

If you're concerned, purchase a gallon bottle of the new "pink" coolant at your local Toyota dealer; Super Long Life Antifreeze Coolant. It is pre-diluted 50/50.

I hope I don't over simplify this for you, but safety is a prime consideration.

I top off mine about once a year in the reservoir. Usually about a half inch add is needed.

First, when Cold, open the radiator cap and inspect it's rubber seal washers for a good seal. If the rubber is cracked or missing on either seal, replace the cap with a new one. (The 2000 RX300 cap is the same as the one used in the 2000 Land Cruiser.)

Insure the radiator is full.

- When "Hot and normal operating temperature", fill the reservoir to about half inch below the Full mark, initially.

- Monitor the level after driving a few days, then fill to the Full mark.

Add coolant only at full operating temperature.

Never add coolant to a hot radiator.

salimshah

First of all, after drain and fill, expect some level drop due to trapped air in the system (most notorious is the cabin heater). So once all the air is removed you get into a stable level stage.

The coolant is not in an air tight environemnt. The over-flow reservoir is open so you will have evaporation. How rapid? Depends upon humidity level and how long the engine compatment remains hot.

Max to min in 18 months is not a problem Still look for crud around the drain bibs and rubber connectors. Smell for steamed coolant when engine is hot.

If you are going from max to min (after reaching the stable level stage) with in a month or week, only then I would be concerned.

Salim

HarrierAWD

I recommend that you fill up only half way when cold. The coolant expands to full when hot. So if you fill up all the way when it's cold, you'll force some coolant out of the system when your RX is running.

I keep it at half way, no loss of coolant. (I'm at 6,000 feet.)

81corolla

Thanks for the input guys.
I'll do as you recommended.

hsmac

so i reported low coolant a couple months ago and added some to the halfway level. i checked again over the last few days and it now hovers around the low level sometimes beneath the line. i don't see any leaks or puddles anywhere -- should i be concerned or what's going on? is there supposed to be an excess reservoir that i could check? i looked around but didn't see one.

salimshah

With the engine cold, open the radiator cap (not the overflow) and top it up. Start the RX and turn the interiors temp to Heat ... [10 degrees higher than ambient]. Watch the temp gauge move and monitor if the level drops inside the radiator. Slowly add new coolant and then top up and put the cap back on. Fill the reservoir to halfway between low and full.

Drive a few days and monitor if the level shifts.

You can also have the system pressure tested.

If you still keep loosing then most likely there is a small leak.

Salim

Drcoffee

Check you transmission Fluid level and color. On occasion, the in radiator transmission cooler will corrode and leak at the tank connections. Because the radiator is under 13-15 psi, the coolant will escape into the transmission causing the ATF to become milky. Referred to as a strawberry milkshake. I doubt thats what is wrong, but its good to check. BTW if your radiator is more than 8 years old, its a good idea to replace it. Its a wear item.

But to answer your dircet question about the head gasket, no it does not look like a head gasket issue. You would see the resevoir overflowing as the engine blows coolant out under extreme pressure. Its Most likely a small hose leak dripping while driving. In a dark area, use a flashlight to search around the engine for wet areas.

aznlapin

You could also get some coolant UV dye and add it to your system. Then use a black light to check for leaks that may be too small to notice otherwise.

hsmac

Thanks for your comments. What is the difference between adding coolant to the reservoir and adding to the radiator? Does a sensor draw from the reservoir to fill the radiator meaning to bypass you could just add to the radiator and monitor it instead; and the coolant level in the radiator is what i should actually be monitoring not the reservoir? I tried to google the overflow can someone please explain where it is? Sorry for the newb questions.

salimshah

The reservoir works on expansion (under higher pressure from radiator) and suction (under low pressure from radiator). If there is large void (or lot of air) in the radiator the expansion is buffered by the air (air being compressible) does not allow pressure to build. So every attempt should be made to clear out the air form the radiator and then the excess fluid moves out to the reservoir and is pulled back into the radiator when the level drops.

Salim

Drcoffee

If you look closely at the radiator cap , it has two valves. The large outer rubber seal with the large spring releases coolant to the resevior above 13-15 psi when the engine is hot. Then there is a small valve in the center of the large valvel. When the engine cools, coolant is drawn back in thru the small valve. Thats why there is a hot and cold mark on the overflow tank. You can overfill the expansion tank/resevior without harming the system, beacuse if there is too much coolant, it just spills out on the street as it expands from heat. If you are losing a small amount of coolant, start by replacing the radiator cap.

if you never replaced the radiator, you should. Its a wear item and small holes can develope from corrosion. They are cheap to buy, roughly $100 for a Denson radiator at www.rockauto.com

hsmac

whoa, i don't see a denso, but i thought radiators costed thousands of $$. is it something easy to replace myself?

thomas1

I had a leak by the thermostat housing. It is located by the battery side of the engine between the two cylinder heads. In my case there was pink residue built up near it. Turned out being an intake manifold leak, the fix was replacing the intake manifold gasket.