To anyone looking at literally my last post, the timing of this one is comedic.

I took a punt on a car I knew needed some work. Including an issue with the heater not blowing hot. I took this on assuming at worst there would be an issue with the heater matrix or a leak etc.

But I am now worried I am looking at a head gasket failure or crack .... I just wanted to see if there is any likelihood of this being something else.

To break it down:

1. No overheating (done a few 40 min drives to test 22 mile) with some high rev driving. Maintains a solid 90 degrees.

2. No white smoke.

3. No gunk under filler cap.

4. No oil in coolant (or not obvious).

5. No power loss.

However;

1. It all started when a colleague noticed a pool of coolant under my car, the reservoir after a long drive had foamed up and leaked it clearly had built up pressure during the drive and was pouring from the bypass tube and some of the lid even. I am a novice at cars to say the least, I stupidly let the car cool, it was still hot about 2.5 hours later, but I let some of the air and it foamed like hell.

2. I had some drained out in the garage but when I got back, by the time I got home the level in the reservoir was very low. Like, below minimum. I topped it up a bit, and ran it with the cap off. It bubbles, over time the bubbles go away but its made worse when I rev the engine.

3. Scared that this was compression gasses entering the coolant (Head gasket failure) I ordered a block test, which claims to have a 99.9% accuracy at detecting this. I have tested twice, for far longer than recommended and the test does not change, suggesting that there are no engine based contaminants in my coolant.

4. Heater won't blow hot. But it warms up a bit when revved, this is most noticeable with the front de-mister blower. The main cabin blowers aren't as effected.

5. The heater matrix pipes has one pipe significantly hotter/warmer to the touch than the other.

In essence, is there anything else that could be causing the bubbling of the coolant and foaming issues. I only "lose" coolant when it bubbles over, I find when I fill the coolant, after a drive it expands exponentially. So I am finding it hard to find the right level or if I need to fill it a bit lower to counteract the effect. I am using the correct coolant. If it wasn't for the negative block tests I wouldn't be so in denial.

I wanted to add as well.

The for a brief period while I was doing the block test (2 to 3x longer than recommended, I was doing it for a good 15 min at temperature with no colour change)

As I revved the car the windscreen blower would actually blow hot again, as it did on my test drive, then suddenly, back to cold.

This is the kind of thing I'm dealing with , it remains over pressure even over night on a cold engine but I keep testing with the block testers and I'm yet to get a positive result. There is some stressing on the resivoir and a lot of the markings are rubbed off as well.

Which engine is this? What year?

The forum sub-section you're in and your profile info don't really match up, and it appears to be a diesel from the engine cover visible in that first pic.

Oh sorry if I have put it in the wrong spot I'm relatively new!

2012 2.0L TDI VRS 109k miles

No worries, just good to know what engine we're dealing with.

I imagine there's going to be an EGR cooler on the back of the engine which might be another source of coolant/pressurised gas interchange, can sometimes bypass that by moving coolant hoses around to eliminate.

Might also be a coolant based intercooler, which might be another non-HG gas entry spot. That would be just pressurised air as opposed to combustion product gases, so wouldn't trigger the chemical kit?

Thank you so muchfor these points to look at, I even doubt if the tests are accurate and I'm just hoping it isn't worst case.

Another point I noticed. Which I assume could be related is where the two pipes go into the heater matrix one is significantly hotter than the other, a night and day difference.

Also, is the coolant based intercooler around the radiator or the radiator at the front? Sorry, as you can probably tell I'm not the most clued up on cars , a recipie for disaster when buying used cars apparently , who would have guessed 😂

Could be a faulty cap?

heater issue sounds like an air lock, both in and out pipes should be similar temp?

Boiling out but constant 90c could be faulty temp sensor.

can you run it long enough for the fans to kick in?

Yeah I have done a couple of runs where the fans were running when I got back but stopped within about 15 seconds of switching the car off so I dont think I've pushed it hard enough for a long overrun yet.

I've been so petrified of HGF and the coolant hat I am reluctant to do the 2hr 100 mile drive to Cardiff.

I've read about the cap, I thought I've my resivoir looked old and stressed that the cap may be as well. I have ordered a new one just in case there is a rare chance this isn't a catastrophic issue.

I do suspect that the resivoir is the original, it's certainly very old looking and has a distinct area of stressing on the left you may be able to just make it out on the other images.

Mine had a "distinct area of stressing" (I like the description!) too. Looked like someone had put a hot metal rod against it. Kind of scorched looking.

I noticed a few weeks ago that this area had actually failed, and there was a hairline split just visible after a drive when hot coolant bubbled at the edges. Luckily it was above the Plimsol line.

I'll have to take a closer look at it , as you've pointed out it doesn't look good anyway.

The plot thickens, the garage took a look at the car, they didn't put it up on the lift due to time but he checked out the resivoir test drove it and experienced the foam first hand.

Unless he is giving me a false sense of hope he says he is 95% sure it's not head gasket related , I assume a mechanic would have easily twigged a HGF otherwise so that's giving me some hope.

He is suggesting it's something related to an attempt to flush it with a product or even dish soap...

The plot thickens.

I've ordered a new cap so ill check that. I think I also need to more closely inspect the resivoir itself.

Washing up liquid's a bad idea. Dishwasher tablets work well though.

I could be wrong, but - My instinct is, the heater matrix is blocked and the system's got a load of rad weld and/or crap in it.

Edited 10 April, 20251 yr by StevesTruck

Yes, rad weld was one of the culprits mentioned it seems to be the foam itself that creates the pressure and flows over.

The fact that one heater matrix pipe is a lot warmer raised my eyebrows as well. I'll try and get the car booked in for a service and then a flush and pray...

In the expansion vessle it looks suspiciously like Kseal or hyperseal etc. It leaves copper coloured fragments in coolant. It may have been added if the previous owner thought the head was cracked or HG had gone. Its supposed to be ok for heater matrix etc according to the instructions but if the matrix was partly clogged it could have finished the job and you have an airlock. I think an coolant flush etc would be on the cards.

Alasdair

Would k seal or similar be used for any other issues other than a head gasket problem? Does it function to seal off anything else?

In a sense in still not out of the woods then which isn't good. I can't imagine a chemical compound will be much of a fix if it is a head gasket problem.

I'd put money on it being some sort of coolant additive (K-Seal). It could be rust from somewhere in the system, but given there's apparently issues with the heater matrix my guess is that.

8 minutes ago, Raizorpoke said:

Would k seal or similar be used for any other issues other than a head gasket problem? Does it function to seal off anything else?

'Permanently seals leaks in the head, head gasket, block, radiator, heater matrix and water pump.'

Edited 11 April, 20251 yr by OccyVRS

Interesting. I did also have some receipts with the car stating the water pump was done in July last year.

I read somewhere that a failing water pump would also cause metal in the expansion tank but I'm not familiar with what type.

By the sounds of it I just have to pray it was used for something to try and cure the heater problem...

At least there's some hope. I have budgeted a but for repairs given the situation with the car and it's price but I'd like to think I won't have to blow the whole lot within a week of ownership on just one issue 😂😅

Can only happen to me!

IMO it looks far too copper-y to be anything else - oxidisation from the liner, blah blah, would at the best bet be dark brown, whereas that stuff looks metallic orange.

Whether or not that’s indicative of your problem, or is a separate issue, is another story however!

Its not good still, I guess.

I probably just have to pray that it was used for something that won't cost the car again to fix so soon!

The garage doesn't seem to think I have a head gasket issue and with the block tests my resivoir overflow issue isn't being caused by engine gases (yet).

I'm just hoping there's something up with the matrix with the lack of flow etc and someone has tried to fix it with something like you mentioned.

Think its the best I can hope for.

I'm still trying to work out the coolant level issue, I'm hoping a flush does something.

I used kseal on a toyota with cracked head. It did work very quickly and lasted for about a year. Never had problems with heater matrix but I ran car with water and citric acid for a good few weeks to flush out rust and gunge etc and then drained and flushed befor adding kseal. See if a magnet will pick up the coppery coloured fragments. If it does its iron/steel if not its copper/alloy It may have been the heater matrix that was leaking? I would try and flush it from engine compartment using a hose and see if water actually passes through it.

Alasdair

Thank you for this tip I will certainly give this a go.