Air Trapped In Engine Water Lines

[bhathiya_u]

Hi,

I saw in a thread that air could be trapped in cooling water circuit and this would give overheating problems.

My CR 42 gives a noice like releasing air bubbles every time i stop the engine (like bloating stomac). Though there is no overheating during my everyday running, once it overheated along the express way. So I'm hesitant to take it again to E01.

Since I hear this 'bubling' noice inside the dash (or may be engine bay, not sure) could it be air trapped in water lines to heaters? If so how could it be resolved. Could an A/C technician do it?

[MkX]

First let us know if your water level in radiator gating low? AFAIK If your water circulation happen properly any air bubbles that trap inside should come automatically unless you don't have a leak some where. If water level doesn't drop and no engine is not heating I don't think you have major Air bubble problem.

However if you hear it in side the dashboard, one possibility would be the A/C heater circuit valve. If the valve doesn't operate properly the water continuously go through the circuit and once engine is off you can hear the sound it returns. I have experienced it in my 121.

[bhathiya_u]

Hi MkX,

Thanks for the reply. Water level in the radiator is static. Overheating only happened in Express way, but not in my day today 35km drive along galle road.

Did you replced the A/C heater circuit valve in your 121? If so how expensive is it? Can an A/C guy do it? That could be a culprit for my lesser cooling A/C as well.

Edited September 17, 2013 by bhathiya_u

[MkX]

I think your over heat in express way, air bubble sound and A/C cooling are not related.

When you drive continuously in 5th gear below 100Kmph engine doesn't burn much fuel. Most of us can see drop in engine temperature. However when you start speeding up more around 110Kmph or above again the temperature rise the RPM increases and heat builds up. However in normal city drive is different to express way drive. There you maintain high RPM continuously for about one hour or two. However engines are designed to this. But with time the radiator, water pump lose it's efficiency. This is why old vehicles sometimes having heating issues in expressway. Drive in express way and observe the heat. If goes up take it out of the expressway in next exit drive in a normal road on 5th gear (keep O/D on if auto) and see. If temperature drops again, check your water pump, radiator and pressure cap condition.

Do complete service for A/C from a good place for AC issue.

[bhathiya_u]

Thanks MkX,

I'm gonna start with an A/C service which is due I think. Got an openion that less oil in A/C compresssor might cause extra load on the engine, which could cause overheating. But not sure when I'll be able to test it along E01. Would come back if I get any improvement.

[Ripper]

When the engine is cool. open the radiator cap and start the engine. top up water as needed and see if you notice any air bubbles.

Just came out of a head replacement myself.

Engine temp went up 80% or so on the highway and would come down rapidly if i slowed down to say 80 or even 90.

No over heating in regular running.

No noticeable loss off cooling fluid either

Traced it to a tiny crack on the head that was leaking combusted gases into the water jacket.

New head, new valve train and now it's all good.

[bhathiya_u]

When the engine is cool. open the radiator cap and start the engine. top up water as needed and see if you notice any air bubbles.

Just came out of a head replacement myself.

Engine temp went up 80% or so on the highway and would come down rapidly if i slowed down to say 80 or even 90.

No over heating in regular running.

No noticeable loss off cooling fluid either

Traced it to a tiny crack on the head that was leaking combusted gases into the water jacket.

New head, new valve train and now it's all good.

Hi Ripper,

Same symptoms as mine.... hope the cause is not as yours

My Radiator is sealed type with no cap on top. I can see only through the save tank. I'd see if I can find any bubbles as u said in save tank.