Have a friend with a 04 LS430 (145k and no serious problems). About a month ago, he was experiencing the classic symptoms of a bad thermostat. So I went in to change and noticed no coolant in the reservoir and could not see any in the radiator. There, was also no indication of leaks anywhere and no coolant smell. So I went on and changed the thermostat to a 70 degree one (vs oem 80- we are in Dallas heat) and drained the radiator and refilled with a 55-45 mixture of antifreeze and water. I did take note that little water came out when I took the thermostat out- about at the same level the coolant was apparently in the radiator.

Fans work fine. However he could tell his fans were running at their highest speeds the last couple of days and last night when we put it on the scanner and at idle in 66 degree weather the coolant temp was as high as 212-214. Once you start driving it moves to about 195. (Worthless gauges on instrument panel and quite a surprise to me (I am a Jag guy) that a car of this level has no coolant level sensor).

This is not a sustainable situation when the Dallas heats starts to show itself at more than 100 degrees.

There are no leaks you can see or smell. When I flushed the radiator with water after draining it ran clear and smooth- so it did not appear to be any blockage.
Coolant is full on radiator and reservoir. Thermostat is new, fans work fine.

He had the timing belt and water pump changed by dealer about 2 years ago (100k). The date is on the car, but seems recent enough for not worrying about that problem.

The only thing I am left with is a major air pocket, unless somehow the radiator has become sludged, but the fluid at the top appears normal.

Thoughts or suggestions?

What is the best way on these cars to remove an air pocket or has been referred to: to "burp" the car? I did not drain the engine as it seemed like the drain **** on the drivers side was frozen shut and I am not one to force things beyond a certain point and since he had a fluid change in the last 2-3 years, did not think that important. Also put on new radiator cap.

Thanks for your help

Tom in Dallas/Plano

 

did you have the heat on high while you put new coolant in?

 

No, we did not do that. Would that be the cause of an air pocket in these cars and if so- the solution?

Thanks

Tom

 

It sounds like you have a clogged radiator. This is a fairly easy DIY. A Denso radiator runs about $120, but you can go with the "Tow Package" version for around $75.

 

Forgetting about the high temp situation, when I replaced my Maxima's radiator, I did run the heat at full, and there wasn't any, even after 20 min.....

I took a towel, covered the radiator cap, and slowly opened it partially....I heard air rush out. I closed it, and redid, and I had heat.....I don't see why this would not work on the LS430, as the reservoir is not pressurized. I understand that this is not the way on some German cars, as the reservoirs are pressurized...

 

I have priced them at Rock Auto. Is there any important difference between the tow and non tow versions?

I am curious as to why you conclude a clogged radiator?

Thanks

Tom

 

By the way- did you open the radiator cap with the towel on it with the engine running or off?

Thanks
Tom

 

The radiator is where coolant eliminates heat. One way to warm up the engine is to restrict coolant flow through the radiator with a thermostat, which is closed below a certain temperature. Once the coolant temperature reaches the set temperature, the thermostat opens to allow coolant to flow through the radiator to diffuse heat. You mentioned that the thermostat has been replaced, so the next potential cause for reduced coolant flow is the radiator itself. My $0.02 worth!

 

You also mentioned that the water pump is around 2 years old and would not be a likely culprit for the reduced coolant flow rate.

 

When I replaced my radiator 2+ years ago, I went with the tow-package version. The 2 versions have the same size plastic caps, but the tow-package version has a thicker metal core than my old radiator. No issues with the replacement so far.

 

I just jumped on the Maxima forum and found a thread where people said to run the motor with the cap off, and heater on.....based on what I said, I don't believe that I idled with the cap off.

https://maxima.org/forums/4th-genera...g-coolant.html

So if the above works, then you should be able to idle the LS430 with the cap off. I think I would try the above first. But in my situation, I opened the radiator cap with a towel, motor hot, and running....so please be very careful if you do that, with a large towel covering the cap and only open partially....I heard a gush of air....

I too am curious about the tow package....isn't that radiator cheaper than the regular one...can we use it?

 

The service manual procedure for bleeding the cooling system is to run the engine at 2500 rpms for a minute with the heater on high. I also used the Denso tow package radiator from Rock auto. It fits fine but it is not the same quality as the original one.

There is a small chance you have a blown head gasket(s) if it was run low on water. I bought mine with blown gaskets and it ran perfectly with no typical issues except coolant consumption. Do you have any residue on the underside of the oil fill cap? Smell coolant in the exhaust?

 

Is the proper procedure, to run the motor at 2500 with the cap off?

It always s**** when we knowingly install something that is not as good....I remember with my Nissan the original said Japan/Calsonic, and the replacement said China. I didn't have to deal with the cooler lines since the car was a stick....on my original I could not get the drain opened, it stripped, what a mess...

 

Cap on. With the cap off the system can't/won't build pressure.

 

That's what I did with the Nissan and it didn't work, yet the forum there says cap off and put a funnel to prevent any overflow/spillage onto the radiator...wonder what the difference is as both cars don't have pressurized reservoirs....I guess envisioning how a brake bleed goes, the air should be making its way into the reservoir....maybe what I did by opening the cap slowly let it all out at once, not slowly...