How to confirm my cooling system is 100%???

[Gandalf]

I'm suspicious that something is wrong. My LS has a Mezeire elec water pump, 170deg t-stat, Ron Davis radiator with shroud and fans plus a catch can from the radiator cap overflow connection.

The temps on idle seem to hover around 175-185 as the t-stat opens and closes. I have confirmed the electric water pump is spinning. This 55g pump has a built-in bypass to help bleed off air in the system (ie: no need to drill t-stat). The top of the radiator, top hose and water pump all appear to get super hot with the top hose seemingly under a lot of pressure. While all this is happening:

1) the lower radiator hose is almost cold to the touch on the radiator end and only mildly warm on the very end by the water pump.
2) there is never any action at the catch can even though I topped the radiator with coolant right to the top before startup.
3) is there air in the system somewhere? And if so, shouldn't it purge itself through the top of the radiator and out the catch can?

I thought maybe the wrong or faulty radiator cap but quick swap with another known good car/cap confirmed ok.

Any thoughts appreciated.
Gregg

[Bryce]

I am not familiar with LS cooling systems, are they a reverse flow system cooling the heads first? Where is the T-stat in the system? Is the radiator cap the highest point in the system?

[67zo6Camaro]

Is that RD radiator a double bypass style, cooling runs in a "U" shape from top to bottom? Both the return "top" intake and suction "bottom" exit tubes are on the same side of the radiator, aka passenger side? Two things to try with trouble shooting. 1. remove thermostate, then seal back up and top off with coolant. Then leave cap off and run motor. You should see coolent moving in top of radiator which would indicate that the pump is pumping through engine and returning coolant to the top of the radiator. Indicating that most likely there is no plug in the motor from the water pump back.

Now 2. Remove or empty the radiator and leave the top and bottor hoses off. Plug the top return line tube and flush water through the radiator from the fill cap. It should flow freely out the bottom suction exit tube. If so this would indicate that the radiator is not plugged and that most likely the motor is plugged from the suction intake to the water pump.

Sounds like if the top of the radiator is hot and the bottom is cold, then the double bypass radiator has a plug in it. Motor is trying to return hot coolant to the radiator but the radiator is not able to return warm/hot coolant back through the bottom hose to the water pump.

Call me, if you want to go over a verbal trouble shoot.

[Gandalf]

I am not familiar with LS cooling systems, are they a reverse flow system cooling the heads first? Where is the T-stat in the system? Is the radiator cap the highest point in the system?

T-Stat is in the upper water pump outlet connection and yes, radiator is the highest point in the system.

Is that RD radiator a double bypass style, cooling runs in a "U" shape from top to bottom? Both the return "top" intake and suction "bottom" exit tubes are on the same side of the radiator, aka passenger side? Two things to try with trouble shooting. 1. remove thermostate, then seal back up and top off with coolant. Then leave cap off and run motor. You should see coolent moving in top of radiator which would indicate that the pump is pumping through engine and returning coolant to the top of the radiator. Indicating that most likely there is no plug in the motor from the water pump back.

Now 2. Remove or empty the radiator and leave the top and bottor hoses off. Plug the top return line tube and flush water through the radiator from the fill cap. It should flow freely out the bottom suction exit tube. If so this would indicate that the radiator is not plugged and that most likely the motor is plugged from the suction intake to the water pump.

Sounds like if the top of the radiator is hot and the bottom is cold, then the double bypass radiator has a plug in it. Motor is trying to return hot coolant to the radiator but the radiator is not able to return warm/hot coolant back through the bottom hose to the water pump.

Call me, if you want to go over a verbal trouble shoot.

Brett - thanks for the very detailed reply and excellent advice. You will be pleased to know this is exactly the 2-step diagnostic advice the Ron Davis tech gave me yesterday. They were extreemly helpful walking through the entire system and listening to the symptoms. They agreed something was not right, mentioning that the bottom hose should be approximately 14degrees cooler than the top under these normal operating conditions with the t-stat open. Definitely not the case here. Also helpful to reset my expectations for the recovery system. He said an 18lb radiator cap on this system configuration and under these conditions will not start to flow until 190-195deg. Again - really good to know.

The only additional step RD gave was to point a temp-gun at the different parts of the system to get some actual temp readings before proceeding.

I followed the advice. Temp gun showed at temp gauge reading of 160-170deg, the top hose approx 150deg and the bottom hose, nearer the waterpump approx 80deg. Both top and lower hoses seem to pump-up hard as if under too much pressure. Again the temps seemed to remain manageable and if the hood were closed you could probably be fooled into thinking things were normal (aside from the slightest hint of steam coming from around the lower connection of the radiator (our only standard hoseclamp used in the system at this time - the others being thermal heat-shrink style).

I let the system cool, dropped the bottom hose and drained the radiator. It flowed out like I would expect. I filled with 1Gal water (getting really tired of the smell and feel of coolant lately!) from the radiator fill neck. It flowed almost equally from the bottom connection and the same amount of fluid was captured. Conclusion - no internal blockage/interference. I unbolted the other end of the bottom hose from the water pump just to be sure no blockage in the hose, connection or anything visually wrong inside that side of the waterpump.

Next I removed the t-stat from the top connection of the water pump and put the rest of the system back together. I filled with water almost to the top of the radiator and ran the pump with the cap off. The pump appeared to flow water through the radiator as expected. The level went down slightly as it worked out some of the trapped air. I then ran the engine and insured that the pump kept flowing (making sure something wasn't robbing power from the pump). As the temps came up, more air was pushed from the system as expected and we topped it off. The noticable change this time - with no t-stat installed, water appeared to be flowing through the system and top and bottom hoses kept a very similar temperature (within 5-10deg). I topped off the radiator once more and this time put the radiator cap on. Again, we saw very similar temps top and bottom. It was also noted that both hoses remained an expected "feel" as in it did not seem they were under an extreem amount of pressure and did not appear rock-hard.

Now we have something to work with.

It's Saturday before I do anything I'm going to watch this t-stat open in boiling water. We wre pretty sure it's opening based on the temps behavior but suspect either not very much or something else going on. I'll then going to put the t-stat back in just for sh*ts and grins before changing anything. Admitedly I'm using water for now until I know for sure we have this cured. I want to see the t-stat put us back to the same error condition or explain why it may or may not be "fixed" (air trapped etc). Mezeire assure me this model pump has a bypass circuit to aid air removal and small flow event when the t-stat is closed. If the same symptoms come back, I will drill the 170deg t-stat and see if that makes any difference (one or two 1/8" holes).

I had bled the system of air but maybe there was something still trapped and it needed more? At least now we are narrowing in on the culpret - I'm glad of that at least. It's the one big-ticket item that's keeping me from reaching second gear for the first time lol! Wish me luck and a trip around the block before the sun sets today!

"News at 11" :-)

[MonzaRacer]

So what actually is your complaint? is it boiling over, running way hot? What? Are you simply going by "feel" of a hose or pipe?
Simply put, a cooling system runs in cycles, goes up thermostat open, coolant flows through rad till it gets cool then thermostat closes, simple, fans kick on when the switch or sending unit tells it too.
I had a guy with a 060 400 sbc ,always ran hot, like 240/250 never cooled down. We drained system and flushed it and switched to Evans NPG+ and tada no pressure on system and still never got hot. He had 3 row aluminum custom radiator made for car, two puller fans and it was controlled by computer.
Now it runs 195 to 205 an cycles fans normally.
Again ,whats the complaint? Too cool, boils over, too hot(dont forget current design engines have fan on temps in 220 to 230 under pressure)?
As for coolant tank most systems rune these 1/4 to 1/2 full hot.
Now WHY IN HECK would anyone need a 18 lb cap? 3x18= 212 degF + 54degF= 266deg F!
Do you actually think its gonna get that hot with out breaking an engine?

Lets get to root of your questions, and I'll try to help. Filling engine completely full hot, engine running, fans cycling, and water pump onmight even keep heater on to make sure heater isnt air locked,,,if you have one.
when its full slap on a 15lb cap, put overflow bottle about 1/3 to 1/2 full, make sure hose is near bottom of overflow tankbut cut it at slant so it wont get sucked onto bottom of catch can.
Go for a drive and see what it does.
AGAIN need a complaint, then we will address issue.

[Vegas69]

Sounds like a sticky t stat. Boil it and I bet you find your problem.