Bubbling coolant not overheating

[lilloco]

I've done a browse of previous issues but not willing to hijack another's thread.....

After doing a maintenance overhaul on my 03 se3 (new belts new coils new plugs) we seem to have a persistent bubbly coolant issue. At first the bottom hose was cold but with tilting the vehicle with hoist and burping the air out she seems more equalized in hose temps. I also replaced the water pump and tsat. Fans do engage and the sensor tested fine. The gauge never registers beyond what is considered normal operating temperature but the reservoir gets quite bubbly. No codes or pre-codes are showing and she runs otherwise beautifully.

Suggestions? Having only worked on motorcycles and jeeps before the closed system is a bit new to me.

Thanks.

 

[GrumpyGel]

Presumably this is a V6. These sorts of threads come up regularly. Good luck, cos even experienced mechanics can sometimes not solve this type of problem on the V6. I should say I have no experience with the V6 and that statement only comes from observing the forum. I say this not to scaremonger, as hopefully you'll get some advice from people who know the V6, but just be careful not to throw to much money at sorting it out as it may never get fixed.

 

[lilloco]

Oh yes my bad this is the ever poopular kv6.

So long as there is some trick to keep it going (like if i stay ontop of the coolant levels to prevent overheating). I have access to a good lower block with intact sleeves and know how to reassemble such an item if it's what it needs. But could it be as simple as the rad needing a super flushing or replace for simplicity sake?

 

[Nodge68]

The V6 is a wet liner engine. It will blow its head gaskets almost instantly if the engine has been run without coolant around the cylinders. A constant stream of bubbles into the tank can be one of 3 things. 1 there's still air in the system. 2 there's a small leak on the inlet side of the water pump. 3 there's a pin hole in a fire ring of the head gasket.
The temperature gauge will always show at the mid point unless the engine temperature exceeds 118°C, at which point it goes into the red.
The V6 is a good engine, but it's as fragile as a Formula 1 car engine and needs to be treated with absolute care if it is to survive. It also quite normal for the bottom rad hose to be cold, even if the top hose is very hot.

 

[lilloco]

Will either of those 3 items lead to permanent failure?

 

[Nodge68]

Will either of those 3 items lead to permanent failure?

It's possible to repair anything, it's just a case of is it worth repairing.