Radiator/cap/ whatever blues
07-10-12, 09:27 PM
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Radiator/cap/ whatever blues
Maybe someone can shed some light on this. Please 
Recently (before yesterday) I had a local shop replace my timing belt and most of related components. I also had him change the thermostat and coolant. He told me that he bled the system from air pockets, but to watch out for either overheating or low coolant level.
I came home, looked at the level in the reservoir - about a 1/4 lower than "FULL" level. Acceptable in my book. Waited till the system cools down, open the radiator cap - it's about an inch lower than cap's rubber gasket mating surface. Low non the less, I added some distilled water, the mechanic for some reason used up all two gallons of my coolant.
I figured it must be the radiator cap issue. Went and bought the new cap and today I repeated the procedure using a new radiator cap. Same or at least similar results. Coolant level in the radiator went slightly down but the expansion reservoir level stays the same.
Isn't the coolant suppose to be drawn from the reservoir when the engine cools off and the coolant contracts?
I must admit that when i bought the car couple of month ago, I noticed that reservoir cap was pried off and was just sitting there on top and the coolant level was low in both the reservoir and the radiator I just attributed it to sloppy dealer mechanics not installing the cap in place. Now, I am a little concerned.
What is going on in your opinion?
02 LS - 83k, all dealer serviced. Never mentioned coolant or radiator issues in the maintenance records.
Thanks!
Just decided to test the little hose that connects the radiator cap's "exhaust" to the reservoir. Using an empty water bottle with a hole in the cap, it blows bubbles through the hose into the reservoir. The passage piece of the radiator where the hose is installed checks out too. Removed the hose completely, brought the engine up to the operating temperature (idling) - nothing comes out of the little pip where the hose is installed. Maybe it is inherently defective radiator that does not allow the cap valve to open us at 16psi like it's suppose to? or the system can't reach the 16psi for some reason...? I am lost, if it was not obvious before
Recently (before yesterday) I had a local shop replace my timing belt and most of related components. I also had him change the thermostat and coolant. He told me that he bled the system from air pockets, but to watch out for either overheating or low coolant level.
I came home, looked at the level in the reservoir - about a 1/4 lower than "FULL" level. Acceptable in my book. Waited till the system cools down, open the radiator cap - it's about an inch lower than cap's rubber gasket mating surface. Low non the less, I added some distilled water, the mechanic for some reason used up all two gallons of my coolant.
I figured it must be the radiator cap issue. Went and bought the new cap and today I repeated the procedure using a new radiator cap. Same or at least similar results. Coolant level in the radiator went slightly down but the expansion reservoir level stays the same.
Isn't the coolant suppose to be drawn from the reservoir when the engine cools off and the coolant contracts?
I must admit that when i bought the car couple of month ago, I noticed that reservoir cap was pried off and was just sitting there on top and the coolant level was low in both the reservoir and the radiator I just attributed it to sloppy dealer mechanics not installing the cap in place. Now, I am a little concerned.
What is going on in your opinion?
02 LS - 83k, all dealer serviced. Never mentioned coolant or radiator issues in the maintenance records.
Thanks!
Just decided to test the little hose that connects the radiator cap's "exhaust" to the reservoir. Using an empty water bottle with a hole in the cap, it blows bubbles through the hose into the reservoir. The passage piece of the radiator where the hose is installed checks out too. Removed the hose completely, brought the engine up to the operating temperature (idling) - nothing comes out of the little pip where the hose is installed. Maybe it is inherently defective radiator that does not allow the cap valve to open us at 16psi like it's suppose to? or the system can't reach the 16psi for some reason...? I am lost, if it was not obvious before
Last edited by nmikmik; 07-10-12 at 10:01 PM. Reason: brain or lack of
07-10-12, 09:56 PM
#2
Lexus Champion
The radiator cap plays a very important role here, is this a genuine part?
If the radiator cap is working properly, I can only think of a few things that would cause your problem. There is still air in the system, so when the coolant cools down, there is not sufficient suction to draw in coolant from the reservoir. The radiator cap is not sealing correctly on the radiator. There is a small leak somewhere, during the cooling cycle air is drawn in instead of coolant. Or perhaps the reservoir cap is not working correctly, there is usually a check valve in them that only opens when there is some pressure or vacuum.
edit - after looking at the parts diagrams, there are two versions of the reservoir cap. Maybe your car has the wrong one? Here are the part numbers, it says something about a mark or no mark on the radiator determines the type of reservoir cap. Lexus calls it a reserve tank.
16376‑50030 MARK A:REFER TO ILLUSTRATION
16405‑46200 NO MARK:REFER TO ILLUSTRATION
BTW this is supposedly a pic of an LS430 engine bay. What is that by the tank, it looks like a radiator inlet what's up with that?
If the radiator cap is working properly, I can only think of a few things that would cause your problem. There is still air in the system, so when the coolant cools down, there is not sufficient suction to draw in coolant from the reservoir. The radiator cap is not sealing correctly on the radiator. There is a small leak somewhere, during the cooling cycle air is drawn in instead of coolant. Or perhaps the reservoir cap is not working correctly, there is usually a check valve in them that only opens when there is some pressure or vacuum.
edit - after looking at the parts diagrams, there are two versions of the reservoir cap. Maybe your car has the wrong one? Here are the part numbers, it says something about a mark or no mark on the radiator determines the type of reservoir cap. Lexus calls it a reserve tank.
16376‑50030 MARK A:REFER TO ILLUSTRATION
16405‑46200 NO MARK:REFER TO ILLUSTRATION
BTW this is supposedly a pic of an LS430 engine bay. What is that by the tank, it looks like a radiator inlet what's up with that?
Last edited by LeX2K; 07-10-12 at 10:04 PM.
07-10-12, 10:16 PM
#3
The radiator cap plays a very important role here, is this a genuine part?
If the radiator cap is working properly, I can only think of a few things that would cause your problem. There is still air in the system, so when the coolant cools down, there is not sufficient suction to draw in coolant from the reservoir. The radiator cap is not sealing correctly on the radiator. There is a small leak somewhere, during the cooling cycle air is drawn in instead of coolant. Or perhaps the reservoir cap is not working correctly, there is usually a check valve in them that only opens when there is some pressure or vacuum.
edit - after looking at the parts diagrams, there are two versions of the reservoir cap. Maybe your car has the wrong one? Here are the part numbers, it says something about a mark or no mark on the radiator determines the type of reservoir cap. Lexus calls it a reserve tank.
16376‑50030 MARK A:REFER TO ILLUSTRATION
16405‑46200 NO MARK:REFER TO ILLUSTRATION
BTW this is supposedly a pic of an LS430 engine bay. What is that by the tank, it looks like a radiator inlet what's up with that?
If the radiator cap is working properly, I can only think of a few things that would cause your problem. There is still air in the system, so when the coolant cools down, there is not sufficient suction to draw in coolant from the reservoir. The radiator cap is not sealing correctly on the radiator. There is a small leak somewhere, during the cooling cycle air is drawn in instead of coolant. Or perhaps the reservoir cap is not working correctly, there is usually a check valve in them that only opens when there is some pressure or vacuum.
edit - after looking at the parts diagrams, there are two versions of the reservoir cap. Maybe your car has the wrong one? Here are the part numbers, it says something about a mark or no mark on the radiator determines the type of reservoir cap. Lexus calls it a reserve tank.
16376‑50030 MARK A:REFER TO ILLUSTRATION
16405‑46200 NO MARK:REFER TO ILLUSTRATION
BTW this is supposedly a pic of an LS430 engine bay. What is that by the tank, it looks like a radiator inlet what's up with that?
As to op, early morning open the radiator cap and fill all the way to the top and next morning check again.
07-10-12, 10:30 PM
#4
Lexus Champion
^^ Ah okay makes sense.
Does the radiator pressurize? If you top off the rad when cool, as the engine warms the expanding coolant has to go somewhere, unless there is significant air in the system then the air will compress.
Does the radiator pressurize? If you top off the rad when cool, as the engine warms the expanding coolant has to go somewhere, unless there is significant air in the system then the air will compress.
07-11-12, 04:07 AM
#5
Lexus Test Driver
btw, do not be confused. there's at least 2 different variants of cooling system on LS430.
one WITH radiator cap (and expansion tank cap), one WITHOUT rad cap (ONLY expansion tank cap). there's markings on the fan shroud, indication what version YOUR car uses.
rads with cap is available aftermarket, the ones without - only original.
just FYI
one WITH radiator cap (and expansion tank cap), one WITHOUT rad cap (ONLY expansion tank cap). there's markings on the fan shroud, indication what version YOUR car uses.
rads with cap is available aftermarket, the ones without - only original.
just FYI
07-11-12, 07:15 AM
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Thank you for replies.
I used an aftermarket cap from Kragen, since the original cap did the same thing I just assumed it was not the cap. Radiator does pressurize, when i open up the cap when it's not completely cooled off, it does spill some coolant out. I suspect there is air in the system and probably was when i bought the car. This is the only logical explanation that I see for all this happening. Now, how do I properly bleed it? I used to raze the front of my car while it was idling to kind of "burp" the system, not sure if it's a good idea on these. My knowledge of the Lexus is ZERO.
This morning the coolant level went down just a bit again. Got to be the air hey?
Is there a way to test that reservoir cap's check valve. There is a possibility that was the reason it was off the mouth when i bought it.
I used an aftermarket cap from Kragen, since the original cap did the same thing I just assumed it was not the cap. Radiator does pressurize, when i open up the cap when it's not completely cooled off, it does spill some coolant out. I suspect there is air in the system and probably was when i bought the car. This is the only logical explanation that I see for all this happening. Now, how do I properly bleed it? I used to raze the front of my car while it was idling to kind of "burp" the system, not sure if it's a good idea on these. My knowledge of the Lexus is ZERO.
This morning the coolant level went down just a bit again. Got to be the air hey?
Is there a way to test that reservoir cap's check valve. There is a possibility that was the reason it was off the mouth when i bought it.
Last edited by nmikmik; 07-11-12 at 07:43 AM.
07-11-12, 09:23 AM
#7
Lexus Champion
Is the Lexus radiator cap new? If not, replace with an original just to be 100% sure the cap is working. Get yourself a Lisle Spill-Free Funnel, it is the easiest way to bleed the cooling system properly without making a mess. It does help to park the car on an incline or raise the front of the car. Make sure the heater control is set to hot.
You can test the reservoir cap check valve by blowing into it.
You can test the reservoir cap check valve by blowing into it.
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07-11-12, 03:19 PM
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Thanks,
Lexus radiator cap looks original or close to it.
The one I got from Kragen does seem to be working, but I will try the new from Lexus. When I came back from the short trip today I removed the connecting hose and the coolant started coming out of the little pip on the radiator. I also air tested the hose that discharges the overflow from the reservoir out to the "street". It tests file, i.e. I can hear the air getting out somewhere. If it does not start pulling from reservoir tonight, I am parking it on the incline tomorrow, just to see if it works.
Lexus radiator cap looks original or close to it.
The one I got from Kragen does seem to be working, but I will try the new from Lexus. When I came back from the short trip today I removed the connecting hose and the coolant started coming out of the little pip on the radiator. I also air tested the hose that discharges the overflow from the reservoir out to the "street". It tests file, i.e. I can hear the air getting out somewhere. If it does not start pulling from reservoir tonight, I am parking it on the incline tomorrow, just to see if it works.
07-11-12, 10:05 PM
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Update,
after all day sitting in my garage and very slowly cooling off. It finally budged.
I marked the level of the coolant with a piece of the duct-tape, it's probably a 501st use of the stuff. Nothing would stick to the reservoir, this did.
And
the level dropped about a 1/4" , so now I am hopeful. Especially that I need (note - need not want) to take a trip to Vegas soon and weather there is usually not very conducive to cooling issues.
after all day sitting in my garage and very slowly cooling off. It finally budged.
I marked the level of the coolant with a piece of the duct-tape, it's probably a 501st use of the stuff. Nothing would stick to the reservoir, this did.
And
the level dropped about a 1/4" , so now I am hopeful. Especially that I need (note - need not want) to take a trip to Vegas soon and weather there is usually not very conducive to cooling issues.
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