Vx no radiator pressure

[Vxutehrt]

Hi guys I've got a vu with an Ecotec and it has been dumping it's coolant/water once it hits 100c
It has a lot of brown build up inside radiator but not oil. Oil looks ok, the digital engine temp says it's only about 100c but seems hotter to be honest.
Also there is no pressure is Radiator hoses they seem soft?
Any ideas I'm going to buy new radiator cap in morning but not sure

 

[Skylarking]

Any brown buildup is usually indicative of rust within a system because the coolant hasn’t been changed as required. And rust residue for your alloy Ecotec block equates to the cast iron cylinder liners (if wiki can be trusted) corroding.

So, it seems you need to consider flushing the system clear any of the brown residue to restore cooling efficiency. This usually means a chemical flush. BUT if an engine cooling system hasn’t been well maintained, such a flush could result in a number of new leaks developing and it depends how bad things actually are. Usually post chemical flush leaks occur within HVAC radiator behind dash, engine radiator and/or possibly hoses, etc...

So I’d suggest pop by a decent mechanic you trust as they can test the radiator cap, the radiator top where the cap sits as well and the general system for coolant leak. They should also test the radiator water for combustion gasses. This should be a five to ten minute job and they shouldn’t charge much for this service but it will give you valuable information as to how big a problem you may have. They could then give you a price to service the cooling system should you desire.

But, if it’s found it’s just the cap, you can do a clean water flush (with low pressure compressed air to agitate the water) and you should be able to get most of the crap out. Remember to have the heater on during the flush. Fill up with new “coolant” and pop on a new cap and hopefully all is good from then on.

Be warned though, driving a car around which does not build up water pressure will lead to loss of water to the point the temp gauge wont work in some cars. This can and does killing engines. So don’t put it off and if you must do short trips, check water level before each drive.

WARNING: on an engine, always check that the hose has no pressure by squeezing the radiator hose before opening the cap to its first stop. Wait for any pressure to be released, if any, then remove cap. If the hose is hard when squeezing, the cooling system has pressure and you should not take the radiator cap off until the coolant pressure drops as it cools. Taking the cap off a hot system can result in serious burns.

 

[Vxutehrt]

Thanks I put a new radiator cap on and got pressure back in the hoses, went for a 30km drive both crusing and in traffic had temp mode on dash it never went over 91 so I hope it's all sorted but I bought new coolant and thermostat so will flush system and install thermostat and coolant in tomorrow.
Never knew a radiator cap is so important.

 

[Skylarking]

Relatively cheap outcome being just the cap.
Good luck with the flush

 

[Immortality]

Yes, a radiator cap is critical to the performance of the cooling system. Monitor your coolant level, brown gunk in the cooling system is also a common sign of the intake gaskets failing as well a rust build up if you don't have the proper corrosion inhibitor protection in your coolant.

 

[Vxutehrt]

How do I get the overflow bottle out from behind my headlight do I have to take the bumper off?
I've got no reserve tank it's weird I'll post a pic maybe previous owner removed it

 

[BarelyHoldenOnTogether]

Why did you let the cooling system get so bad? You're obviously using water since there's brown rust build-up. Stop using water. Do a flush and use proper coolant. Cars this side of the 1972 202 red motor don't run well with water alone as it corrodes everything and doesn't cool the engine hardware properly. More modern cars cooling system parts rely on the lubricating and protecting properties of coolant to ensure water pumps dont seize up.

You can flush it out at home and do a good job.
I usually recommend firstly flushing the radiator by taking the hoses off and running the hose through the radiator until clean water comes through.
Then remove the thermostat and give that a nice clean - test it open/closes by putting it in hot water if it opens, all good.
Clean out the overflow bottle too.
Then I'd fill a big 20L bucket with tap water and let it sit in the sun to warm up a bit. Reconnect the bottom radiator hose, but leave the top radiator hose disconnected. Fill the radiator with water, then run the engine with the heater running at full temp, and wait until you see water coming out of the top hose. As water comes out, keep filling up the radiator with the warm water in the bucket until you see clear water coming out of the top hose.
Then reconnect the top hose, undo bottom hose to flush out the radiator and add 50/50 coolant/water mix to the radiator.

 

[Trevor loves holden.]

More modern cars cooling system parts rely on the lubricating and protecting properties of coolant to ensure water pumps dont seize up.

Not all right, no lubricant in coolant.

 

[Vxutehrt]

I'm still having overheating issue just found my tube going to pod filter is badly split would this be the cause??

 

[Trevor loves holden.]

As long as there no air sucking in after the MAF as it will make it run crap, I say buy a new radiator yours is probably partly blocked if it was that bad, if it was me I would replace your water pump too.