Coolant leaking out of the bottle top

[Viper Driver]

I had the dreaded coolant hose blow out on me a few months ago, and luckily I caught it immediately before there was a chance for any damage to occur. I did the DIY replacement of all of the coolant hoses, and then went through the lengthy process of bleeding all of the air out of the system. I'm fairly confident that everything was done correctly. However, I am experiencing something that didn't happen before the coolant hose change that worries me a bit.

When I drive the car, the engine temperature is always in the middle of the gauge (ie., NORMAL). However, I have had at least five instances where coolant has leaked out of the top of the SOS coolant bottle I have installed. I'm not sure if it's when I'm driving, or after I've parked the car. I wash my car in the garage where it's parked, so any coolant on the floor would be washed away. It seems to be after my longer drives (>30 minutes) that this is happening. Again, I have no indications when I'm driving the car that the car is in danger of overheating.

Anyways, last night after commuting home from work, I heard a "gurgling" sound coming from the coolant bottle. It sounded like it was filling up or something. After everything cooled down, I checked underneath the car and didn't see anything pooling on the floor. I took the bottle cap off and the coolant bottle was about 1/2 way full.

The coolant is leaking out of the "radiator" cap area and dripping off of the side of the overflow bottle. I've had to wipe the bottle off about four or five times now, and I have not added any more coolant since the hose change. I figured that if I overfilled the coolant, it might overflow and leak out once or twice but not five times spread out over a couple of months.

Does anyone have a similar experience, or any possible solution/cause for this? Worst case, is there any chance this might be somehow caused by there still being some air somewhere in the coolant lines and cavitating the water pump or something? I'd think that if that were the case, the problem would be a lot worse (and a lot more noticeable) by now. Could it be the bottle cap itself?

Thanks! :smile:

 

[dalybo]

try replacing the radiator cap on the coolant recovery tank; it may have a bad seal which could be the source of your leaking coolant issues. fyi...it happened to me!

 

[Doc308]

I've not had this problem with my NSX to date, but it is not at all uncommon on Ferrari 308's. The set up is the same as the NSX and the overflow is typically due to one of 3 things: bad cap ( not holding enough pressure), air in the system, or an overfilled coolant tank . Of course, there is also the possibility of a clog somewhere in the system too, but I'd bet the problem is one of the first 3 possibilities . One more possibility ( and this did happen with my NSX). I had a very small crack just above the midpoint of the coolant bottle and it would only leak after the car was driven because the coolant level would rise up to the crack with the operating temperature. Once cooled down, the level would drop and it therefore would not leak once cooled off and sitting still

 

[nsxtasy]

I've had to replace my cap at least twice so far.

 

[Hugh]

The coolant is leaking out of the "radiator" cap area and dripping off of the side of the overflow bottle. I've had to wipe the bottle off about four or five times now, and I have not added any more coolant since the hose change. I figured that if I overfilled the coolant, it might overflow and leak out once or twice but not five times spread out over a couple of months.

Very good chance your bottle is cracked near the mounting bolts as a previous poster suggested. Since your car is a '91, if it's the original bottle I can almost guarantee it. Oh and the cap is probably bad too.

 

[Viper Driver]

It's not a stock bottle.......It's a fairly-new SOS coolant bottle. It's coming out at the radiator cap.

:smile:

 

[Hugh]

It's not a stock bottle.......It's a fairly-new SOS coolant bottle. It's coming out at the radiator cap.

:smile:

Those damn Percodans and late night hours really screw up my reading comprehension skills.

 

[OLDMNSX]

Along with the previous suggestions, which are all good, I would rebleed the coolant system.

Remember :
1. The top of the radiator
2. The top of the solid hose at the heater core, nose compartment. It has a small rubber cap with a squeeze clamp.
3. Bleeder at the forward firewall in engine compartment
4. Bleeder at the thermostat housing
5. Open the cap on the reservoir tank to allow the fluid to flow.

Do this with the system cold. Watch for any small bubbles at all of the bleeders.

When I did my complete drain and flush I found small bubbles on the second bleed from some of the bleeders.

 

[Doc308]

Re: bleeding, Larry B. indicated to me that jacking up the rear of the car will result in a more thorough bleeding process. Larry--pipe in and correct me if I misquoted you.

 

[Viper Driver]

Along with the previous suggestions, which are all good, I would rebleed the coolant system.

Remember :
1. The top of the radiator
2. The top of the solid hose at the heater core, nose compartment. It has a small rubber cap with a squeeze clamp.
3. Bleeder at the forward firewall in engine compartment
4. Bleeder at the thermostat housing
5. Open the cap on the reservoir tank to allow the fluid to flow.

Do this with the system cold. Watch for any small bubbles at all of the bleeders.

When I did my complete drain and flush I found small bubbles on the second bleed from some of the bleeders.

Thanks for the suggestion. I just got done doing the bleed again here in the garage, and there was clear blue coolant and no bubbles flowing out of each bleed point on the car. So, at this point, I think it's probably just the bottle cap.

 

[OLDMNSX]

Viper Driver

I would have to agree with you. I bet the new coolant tank cap will fix you up. Be sure to get a genuine Acura Cap, don't get a cheep-o cap from Auto Zone or Schucks (my moto is if it comes in a can or bottle it's OK, otherwise watch out). Let us know.

Something else that I did with mine was take a black Sharpie and mark the hot and cold level. A one inch black mark on the "Ol White Milk Jug" is kind of nice to have to keep track of any change in the level over time. Open the cap and stick your MagLite in the hole and point it toward the side where you want to make the mark and the level will stick out like a sore thomb.

Brad