Headgasket or thermostat

[philthehill]

I have seen worse.
I left a 948cc block filled with citrus acid (6 table spoons per litre of water) for a couple of weeks and the water jacket came up like new.
If you are absolutely desperate and the engine is out you can get good access to the water jacket and drain plug area through the rear welch/core plug.

[davidpidge]

I'll give citric another go. I suppose the issue is if there's a sever blockage it won't ever pentrate and get around the entire block.

[svenedin]

I'll give citric another go. I suppose the issue is if there's a sever blockage it won't ever pentrate and get around the entire block.

I suppose the citric acid solution should get to either side of the blockage and hopefully dissolve it away from both sides. In your situation I would run the citric acid round hot with the engine up to temperature (with the car static in the garage). I'd repeat that several times. It's your car of course and clearly up to you what you want to do. I use citric acid in a 95 C cycle in my washing machine and also to descale the kettle and shower valves (which are brass). No harm has happened to these items after many years of descaling.

Stephen

[davidpidge]

That's good to know. Considering the state of the engine I'm not worried about damaging anything. Hoses and radiators are easy to replace.

[svenedin]

That's good to know. Considering the state of the engine I'm not worried about damaging anything. Hoses and radiators are easy to replace.

Good luck. Please let us know how you get on. PS Citric acid can be bought cheaply in bulk. It is used in pickling, to make “bath bombs” for de-scaling, as a “stop” bath in film photography etc.

Stephen

[davidpidge]

The citric acid has been in the engine for a couple of weeks now and I've done a few short drives where the engine is always very hot. Just driven to work after leaving the car sat for over a week and removed the rear drain plug from the block. There is finally some water making it's way through. It didn't run out the hole but it's definitely not just a lump of sludge anymore. I poked a knitting needle in and it goes in and up around 70mm at most.

I've topped up the water and added a bit more citric acid. I'll keep driving it and hopefully it'll work through slowly.

I assume if you have the drain plug out and the engine running then coolant should flow out from a healthy clean engine?

[svenedin]

Water pours out if you remove the drain plug and there is no blockage. I’d suggest using something like coat hanger wire. The channel is not horizontal for much distance (see previous threads where Phil has posted a picture of a cutaway engine showing the channel). You are definitely making progress. Now there is some flow there’s more chance of the citric acid finishing the job.

[oliver90owner]

Top and bottom hoses get very hot once engine heats up.

That could mean the rad is blocked, apart from a small section. Do check that the whole rad gets hot.

Not, by any chance, refitted the fan the wrong way round? I’ve seen it done before now.

[davidpidge]

Fan the wrong way round could be possible but when I've had hoses off rad and flushed it, water ran through fast and free.

[Monty-4]

The thermostat looks mint.
20230523_180113.jpg

It's amazing what these engines can take before failing sometimes.

[oliver90owner]

Fan the wrong way round could be possible but when I've had hoses off rad and flushed it, water ran through fast and free.

Not necessarily a measure of heat dissipation. Check the whole width of the radiator tubes. That is, of course, with the fan belt removed (or the fan removed).

I used to fit a much larger fan/pump pulley on my cars back in the 70s - as long as they didn’t get too hot in heavy/slow traffic. I’ve had to sort out dozens of agricultural overheating problems in my time. The cure is often quite obvious, once diagnosed. One of our favourite radiator leak repairs involved sealing off some of the cooling area with ‘Plastic Padding’ (or P-38 body filler) - often after some disaster with the fan (engine hit rad or pump shaft failures, for instance).

I have one radiator (75 years old) which has had more than a few tubes simply isolated by soldering at the top and bottom of leaking tubes. A similar radiator core was replaced with one row fewer tubes. It will still cool adequately in our climate, even when worked hard (at least for most of the year).

The thermostat looks mint.

I’ve seen umpteen thermostats that ‘looked mint’ but didn’t test out satisfactorily. The only way is to test them, not assume they are good because thry look OK.