Broken heating after 'K Seal'?

Good morning,

So, adding stuff like that is a big no, no. It will seal the leak and get you off the side of the road, but it gums up and clogs everything in the system. Even after replacing the thermostat and replacing the coolant there probably is still some in there possibly keeping the new thermostat open.

Getting that stuff completely out is going to be your first step. It has probably clogged the pump or the radiator and not allowing the coolant to flow properly.

You could try flushing the coolant yourself by doing what you have already done. Drain and replace the coolant. After you replace the coolant drain it and add more then run it and drain it. But this is going to cost you a lot of money in coolant and to be honest you will never get it all out of the radiator.

The best way in my opinion is to have it flushed by a professional so they can use a machine which will move the coolant back and forth. This will help get all of it out.

I would replace the thermostat housing that you said was cracked so it doesn't leak.

You are more than likely going to have to replace the water pump, thermostat, hoses, radiator and possibly the heater core. You can probably rinse out the expansion tank and re-use it as well as the hoses. Hoses are cheap though so since you will be taking it all apart, I would just replace them with new clamps.

The shop is more than likely going to recommend replacing these things and it will be up to you if you want them to replace them. If you feel comfortable doing the work, I would just get it towed home and replace the parts myself. Get the quote from the dealer though so you have all the chevy part numbers. This will help you get the right parts the first time.

If you don't replace those parts and they have anything in them, it could clog the heater core again or something else and you will have to flush everything back out.

In my opinion this stuff shouldn't be on the market. My advice is never use any liquid fixes in a bottle for any part of your vehicle. It might get you off the side of the road, but it will cost you in the long run.

You might be able to clean the pump and reuse the new thermostat you put in but the radiator I would definitely replace. You may be able to salvage the heater core by flushing it but if you do all this work and there is something still in there it could plug the system right back up.

Here are some links to information to help you replace these parts:

https://www.2carpros.com/articles/replace-heater-core

https://www.2carpros.com/articles/how-to-replace-a-car-radiator

https://www.2carpros.com/articles/water-pump-replacement


So, in conclusion go get it flushed. I would personally go to the dealer and have it done. Tell them what you put in it and what you have done so far.

Then decide if you want them to replace those parts I mentioned earlier, if not do not drive it home, have it towed. Do not run it at all and then remove those parts and replace them. The coolant temperature sensor should not have to be replaced. I would just remove it and make sure it is clean. Then re-add fresh coolant.

Unfortunately, in my opinion this is the only way to make sure it is all out of your cooling system. If it were my vehicle, this is exactly what I would do.

Let me know how it goes and if you have any more questions just let me know.

Thank you,
Brendon

Hi Brendon,

Thank you so much for your detailed feedback :)

Here's an update:

I changed the thermostat again and repaired the thermostat gasket properly but that didn't seem to achieve anything.

I also changed the heater matrix / heater core for a brand new one and this has definitely made an improvement. :)

Hot coolant is definitely getting into the heater core, and I am getting some hot air coming through into the cabin (which is good!) but the car's heating is still acting a bit strange...

The heating still takes quite a while to get going and is only warm (rather than hot).
Additionally, this warm air only comes out on the driver's side!
The air coming out of the passenger's side is cold.
I also have to drive the car pretty hard for the warm air that does come out to increase in temperature.
Driving more slowly will usually see a reduction in temperature again.

So, I think there are 2 or 3 issues:

1. The passenger's side still blows cold air with the heating on.
I wonder if this could be a broken blend door. When removing interior panels to gain access to the heater core, I did see a couple of loose pieces of broken plastic so that could be the issue?

2. The warm/hot air that does come out the driver's side is still pretty weak and very dependent on driving style.

3. I'm still not sure that the thermostat is completely fixed as the coolant takes quite a while to warm up.

Many thanks for your help.

Good evening,

So, it does sound like either a broken blend door or an actuator. Could be both.
It depends too on the heating controls. Some are automatic, some are manual. Automatic could indicate an issue with the control unit itself. Manual controls and the fact that you saw some broken pieces of plastic, I would bet more on the doors. I would replace the actuator and the door at the same time. Dorman isn't a bad brand to use.

Are your controls automatic or manual?

As far as the heat being weak that sounds like you still have that stuff in your system. If that sealant is still in there, it could be holding the thermostat open and that is why it is taking so long to warm up.

If the radiator was clogged or the water pump wasn't moving the coolant around it would be more likely your engine would overheat. So, it's possible something is holding the thermostat open and causing an over-cooling condition.

I am finding multiple thermostats with different temperature ratings. It's definitely possible they gave you the wrong one. This would mean it is opening too early and also causing an over-cooling condition.

What does your engine temperature gauge get too?

Can you send me a picture of it when it's warmed up just idling?

Does your cooling fan turn on?

If you send me your entire 17-digit VIN I can look up the option codes and see what temperature thermostat is supposed to be and find the part number. Then we can see if it's the right one. It does happen I just want to be able to rule it out as a possibility.

Unfortunately, it is also possible more stuff got into the new heater core. I would try flushing it and see if it gets hotter.

Can I also have the part number and brand you bought as well?

Thank you,
Brendon

Hi Brendon,

Thanks again for your reply.

The heating control is manual - so this also points towards the doors being broken. Now I think about it, when I first purchased the car, the central left cabin-facing air vent was stuck hard in a fixed position. I had to force this out of position to get it to move and this could have broken blend doors further down inside the HVAC plastic routing???

The car still seems to be acting as if the thermostat is stuck open...
1) Coolant takes a very long time to warm up.
2) Hot air in the cabin is warm more than hot.
3) Heating only gets hotter when driving fast for long durations.
4) Heating cools down again if stuck in traffic or driving slower.

However, the thermostat has been changed twice and it still behaves in the same way.

Is it possible that there could be an issue with the thermostat housing and surrounding pipes rather than the thermostat itself which could still make the car behave in the same way as if the thermostat was open/defective?

Even though the coolant temperature takes a long time to rise, it does get to the correct level (just below halfway on the gauge) and it does manage to stay at exactly that point - even if the cabin heating starts to cool again.
So, the engine itself is probably operating at the right temperature - it's just the internal cabin heating that suffers.

The original thermostat I removed was rated at 89 degrees.
The replacements I have tried are also all rated to 89 degrees, but they are all slightly different shapes and lengths - but they were all advertised as able to fit the vehicle.

I also checked the air conditioning on cold and that works absolutely fine across all vents - gets very cold so no problems there - the only problem is the heating.

When the coolant temperature warms up, the main engine fan does come on without any problems. A couple of times recently, the fan has continued running once the car is turned off - as if it's overheated - even though the cabin heating is weak - but it's only done that a couple of times.

I've also plugged in a pretty basic OBD2 scanner but it's not reporting any codes.

I've also attached some photos if that helps.

Thanks again.
Chris

Good morning, Chris,

When you get a chance can you send me your entire 17-digit VIN?

I need some more detailed information that is only available with the VIN because of the different types of models. I am not even getting an engine size of 1.7L. They are all 1.4L and 1.8L.

I think you might have air in the cooling system.

I would remove the radiator cap when the engine is cold. Start it and let it warm up, watching it while it does and squeezing the larger hoses to see if you see any air bubbles coming out. Then adding coolant. Do this until you get no more air coming out and see if heat improves. Also make sure you are using a 50/50 mix of DEXCOOL and clean water. You can buy it pre-mixed. I prefer the pre-mixed.

Here is a previous article for a different motor but your radiator might have this same vent and see if it will help:

https://www.2carpros.com/questions/antifreeze-not-circulating

I'm thinking there is a vent to help bleed the coolant in the motor. But will need the VIN to look further. This could cause the coolant to not flow as well as it should.

I also want to check the thermostat as 89 degrees sounds really low. My trucks is 195 degrees. Normal operating temperature is between 195 to 210 degrees.

Also, some turbo charged vehicles keep the cooling fan running after the vehicle is off to cool it down to prevent damage to the turbo and even use an electric water pump to move coolant around.

As far as the HVAC system there is many valves and doors because of the dual climate control. There is a separate blend door for each side. I added a picture, but this is from a 1.8L GAS. The system should be fairly close though.

I noticed your vehicle is a right-hand drive in your pictures. Is this vehicle from the U.S.?

If you could give me your VIN that would really help to make sure our information is accurate and get this issue solved.

Thank you,
Brendon

I just suddenly remembered I hadn’t told you why I initially used the 'Steel Seal' and 'K Seal' products.

As I was constantly losing coolant, I used some ultra-violet dye to try and find where the leak was coming from.

I was worried I might have a blown head gasket.
I poured ultra-violet dye into the coolant expansion tank and later shone the ultraviolet torch
I poured the dye into the coolant expansion tank and later used an ultraviolet torch to find the dye inside the engine ender the oil cap.

The is what then caused me to then use the liquid sealants as I feared I may have a blown head gasket.

If the head gasket is blown, would that cause symptoms similar to the thermostat being open - with the heating failing to warm up quickly?

I know a blown head gasket can cause heating to fail due to coolant leak.
However, even when I first refill the coolant the heating still fails to warm up quickly.

Just to confirm I’m in the UK, hence the right-hand drive. The 89 degrees is Celsius - so 192 Fahrenheit. The 1.7 is a diesel spec which you might not have in the US.

Will send over VIN soon.

Thanks

Good morning, Chris,

Okay. Makes sense why I couldn't find that motor size and 89 degrees makes since now. Unfortunately, even your VIN won't help me. I only have access to U.S. vehicle information.

If you found the dye under the oil cap after adding the dye to the coolant system only. I would say the head gasket is blown. A cracked head can cause this as well. Both are going to require a rebuild.

I would change the oil after it has sat and cooled off a bit. The oil will float on the top of the coolant so if it's really bad it will pour out coolant then the oil will come out. Sounds like coolant is getting into to the oil for sure.

Will it affect you heat? Well, if coolant is leaking out air must be getting in. A lot of times its combustion gases like a gas called Knox or nitrogen oxides. There is a liquid you can use to test for this. It's usually blue and turns green if Knox gas is present which is a by-product of the combustion process. I noticed the lines for your heater core are both on the bottom. It's possible the gases are getting trapped at the top of the heater core. Leaving the heater core half full of air and that could affect heat output. It's also possible you still have some of that stuff in your cooling system as it is usually quite a process to remove fully.

Since you are having issues with the blend doors and both pipes to the heater core are hot. It's entirely possible the driver's side isn't fully in the heat position and stuck more in between causing warm air instead of hot.

To use the block check liquid put it on the top of the coolant reservoir after filling it to the line with the fluid. Squeeze the ball over and over while the engine heats up. Makes sure the coolant doesn't go into the test kit, you may have to remove some coolant to perform this test. If there are nitrogen oxides present it will change color to either yellow or green. If it changes color, I would say it is the head being cracked or a blown head gasket.

Some vehicles have an oil cooler built into the radiator. If it is cracked coolant will get into the oil but you more than likely will see oil in the coolant as well.

White smoke coming out of the tail pipe is another sign the head gasket is blown but during winter is hard to tell.

I have seen coolant tanks blowing bubbles before too because the head gasket was so bad.

The turbo charger, if your vehicle has one, is another possible area. You might have a trouble code for low boost as well.

I would honestly drain the oil and see what it looks like. If you see a bunch of coolant, you know you found your issue. If you don't see anything obvious, I would leave the plug off with the drain pan underneath it. Use a coolant pressure tester and pump up the coolant system to about 13-15 PSI. I will add a picture. Leave it for a while, about 30 minutes and see if coolant starts dripping out. If so, you definitely have a bad gasket, cracked head or a damaged block. If nothing drips out fill it back up with oil and use the liquid block check.

Do those 3 things and see what you come up with and let me know. I will be here. I am going to look on my end and see what information I can get to help.

Cheers,
Brendon