Went through flood - preparation to attempt to restart?

Possible damage is an engine that is scrap, having ingested water. Your breakdown geezer should have told you about that. First action now should be to get a compression test carried out. Then come back and tell us the results.

Steve

Will an AA/RAC guy do a compression test, are they equipped/capable of doing such a thing?

Maybe somebody could give me some instructions to do a compression test? What equipment from halfrauds would I need to buy.

Doesn't the engine need to run first to do a compression test? I just want to make sure I don't do any more damage by trying to restart it if there is water inside the engine. Would a small amount of water inside a engine really do much damage when starting it up? As I thought it was the hot engine suddenly coming into contact with cold water which caused the damage, rather than just the fact of water getting inside.

Snip The guy from the breakdown should not have asked you to turn the engine over IF he was aware of water possibly being drawn into the engine. However you cannot compress a liquid and more than likely if any damage has been done it was during driving through the puddle. Did the car turn over ok after this or did it make a sound like when you try to start it in gear by mistake. Worst case scenario is an engine with bent conrods which is expensive to repair. Like the guys say do a compression test first and see what the results are. You just buy a tester remove the sparkplugs and screw the tester in and turn the engine over on the starter. Hope this helps you get going let us know the readings.

Ok, I am that guy! (though probably not the actual one in this case!)

When we get to a flood cut out, there are two possibilities.

1) Water has entered the inlet, into the engine while it was running, the engine is already dead. In this case turning it over will do no further harm.

2) Water hasn't entered the inlet, in this case the engine can be turned over causing no harm.

So you see, whatever the circumstances, by the time we get there, turning the engine over will not cause any problem.

I can see the logic of the above. However when I was involved in rallying I drowned my car out a number of times. I also helped others in the same state. I always removed plugs and cranked it until no more water came out. Often there was a significant amount in each cylinder. Clearly I couldn't say there was enough to cause hydraulic damage but I'm guessing there often was.

Surely it would take so little time to do that it would be a sensible precaution?

Chris

We wouldn't generally do a compression test at roadside, a compression test generally is only required to tell you if an engine is worn out, and has lower than normal compression. Flood damaged engines will generally have no compression whatsoever (in the case of holed pistons etc) which you can tell be ear, or be seized, which is pretty obvious to spot!

A compression tester!! (yep, it really is that simple!) the gunsons cheapo one will do for this job.

To use, firstly, disconnect the ignition coil(low tension side). remove a spark plug, screw in the tester, and attempt to start the engine, holding the throttle wide open. note the reading on the tester, Repeat for all cylinders. Important things to note, test must be done with sparkplugs fitted to the cylinders not actually under test, and the throttle must be open while turning.

No, the test is done using the starter. Make sure your battery is well charged. The reading you will get can be expected to be somewhat lower that the specification, as the spec will be for a hot engine, but it will give you a pretty good idea. Tell me what car it is, and I will look up the pressure for you. As an example. a 1600 sierra would be 12bar. though I wouldn't worry too much if you got anything higher that 9bar on a cold engine. The main thing to look for is for variation between the cylinders, e.g. if you get 11,11,8,8, then the likely fault is a head gasket failure between 3 and 4, or if you get 11,7,11,11. then number 2 has something wrong, etc.

If your really worried, remove all the inlet pipework to dry it out, (no need to refit it until after the compression test, if it is in the way of access to the plugs etc), and remove all the sparkplugs before spinning the engine over on the starter motor for a few seconds (full throttle to allow plenty of air through)

I only answered the questions asked an was in no way laying blame or slagging anyone off.

Why can't you take out all the plugs first and then do the comp test simon surely the test is only relevent to each single cylinder and valve setup. I can see why you would leave them all in for a leakdown test.

Is there any danger in me simply just trying to see if it will start/run now that I have charged up the battery fully? Or will an oil change and/or compression test be necessary before attempting this?

Do the RAC/AA/green flag guys carry a compression tester with them? And one of those long spark plug remover tools? (As I think it requires one). Is carrying out a compression test a one man job, ie does the needle remain at the reading to give you a chance to look at it, as hard to turn over motor and read gauge with bonnet it in way.

CHeck the cambelts still timed right then spin it over without the sparkplugs in & see if any water comes out.

All the screw in guages hold the reading for you

--

Yes they do and can

Steve

And the long spark plug remover tool?

Should,nt be a problem either.

So you work as a patrolman for one of these AA/RAC/Green flag outfits do u?

equipped/capable

Yes I do.

Steve

Personally I would try it, unless the design of the inlet is such that there may be trapped water in there somewhere, which may get sucked in when it revs.(e.g. on a XJ6, there is a large dip just before the throttle body, which tends to hold water)

Not usually, see above, near the top of the post somewhere!

Yes.

The gauge will hold the highest reading till you reset it.

Oh, Hi Steve (waves) who do you work for then? I work for a garage in Blackpool, contracting to AA/RAC/green flag etc.

The other guy Steev? said he carried a compression tester, so maybe he work for the AA/RAC and maybe the contractors don't bother to carry these?

The air filter inlet casing etc is simple enough to dismantle and dry but that's not the concern. I was more concerned about any water that still could be inside the engine and the assumption trying to start it with water in could cause damage. Aren't you supposed to remove the spark plugs and crank it to get any possible water out? What about draining the oil? I am not a mechanic this is just what I have gathered from reading on here.

Would be a lot easier just to see if it will start and run, but obviously this would be foolish if its likely to cause damage. What do you think?

PS Do you give a higher priority to Green Flag customers to avoid them getting the £10 if you take longer than an hour to arrive?

I dont personally carry a compresion tester, and AFAIAA, it isnt part of the AA kit, I will ask one of their patrols next time they drop by the garage.

Like I said somewhere, pull the plugs out and spin it over a bit, will clear any reamaining water, then give it a try to start.

No! Jobs are handled in the order they arrive