[Flowers]

Rover 420 smoking white, rough running coolant loss and running bad no mayo.


Could this be head gasket or a fuel issue with incidental coolant loss? Is there anyone who can guide me through this I am near Coventry.

[220 GSi turbo]

White smoke and coolant loss together with rough running is generally a sign of head gasket failure and it is possible for it to fail without oil and water mixing. If oil and water don't mix, you don't end up with mayo in the cam cover and cappucino in the header tank! I would point out, though, at this time of the year it can be quite normal for 'steam' (rather than white smoke) to come out of the exhaust, because the catalyst produces water as part of its job.

If there are no obvious signs of coolant loss, that would add weight to the argument.

T-series engines are not generally prone to head gasket failure, but like most engines with an alloy head, if the coolant has not been renewed for a long time it can lead to corrosion of the waterways in the cylinder head.

Ideally, you should get somebody to do a pressure test and perhaps use a gas detector in the header tank to look for signs of combustion gas getting in the coolant.

[Flowers]

White smoke and coolant loss together with rough running is generally a sign of head gasket failure and it is possible for it to fail without oil and water mixing. If oil and water don't mix, you don't end up with mayo in the cam cover and cappucino in the header tank! I would point out, though, at this time of the year it can be quite normal for 'steam' (rather than white smoke) to come out of the exhaust, because the catalyst produces water as part of its job.

If there are no obvious signs of coolant loss, that would add weight to the argument.

T-series engines are not generally prone to head gasket failure, but like most engines with an alloy head, if the coolant has not been renewed for a long time it can lead to corrosion of the waterways in the cylinder head.

Ideally, you should get somebody to do a pressure test and perhaps use a gas detector in the header tank to look for signs of combustion gas getting in the coolant.

I will try this. If it comes to it and it does need a head gasket what gasket does it need? I have heard about dowels needing to be replaced? What would a parts list look like. Do you know of any of these engines being broken or sold I may take a spare head.

Also are there any reasonably priced mechanics who could help me if it comes to that.

[itcaptainslow]

As Paul says, I would get the issue properly diagnosed before firing a parts cannon at the car. The following tests are a good start;

-Cooling system pressure test (this will hopefully identify the location of the coolant loss)
-A “block” sniff test; this detects exhaust gases in the cooling system. If the car fails this, it’s an indication of either a cracked head/block or head gasket failure-either way the engine will need stripping to identify the problem.
-A compression test; you want to see readings of 150psi plus across all four cylinders, within 10psi of each other. One or more cylinders down indicates either a mechanical issue within that cylinder (e.g. a valve not seating correctly, worn bores/rings) or a head gasket leak.

The equipment to perform these tests varies in cost, up to around £100 for a cooling system pressure test kit-if you’ve not got any of these, it might be worth investing in the services of a trusted garage.

[Flowers]

As Paul says, I would get the issue properly diagnosed before firing a parts cannon at the car. The following tests are a good start;

-Cooling system pressure test (this will hopefully identify the location of the coolant loss)
-A “block” sniff test; this detects exhaust gases in the cooling system. If the car fails this, it’s an indication of either a cracked head/block or head gasket failure-either way the engine will need stripping to identify the problem.
-A compression test; you want to see readings of 150psi plus across all four cylinders, within 10psi of each other. One or more cylinders down indicates either a mechanical issue within that cylinder (e.g. a valve not seating correctly, worn bores/rings) or a head gasket leak.

The equipment to perform these tests varies in cost, up to around £100 for a cooling system pressure test kit-if you’ve not got any of these, it might be worth investing in the services of a trusted garage.

I have done a compression test, it is showing 125 on all cylinders, not sure how reliable these testers are but there was no variance betwen cylinders.

Block test i have tried there was no change, i used a old kit i had i will try another this week.

Any thoughts on where i go from here? I'm not sure if this is condensation and i cant give the car a run as no mot yet.

[itcaptainslow]

First thing that strikes me is those compressions are a little low…

[Flowers]

First thing that strikes me is those compressions are a little low…

Yes indeed the tester is a Chinese tester not sure how accurate the readings usually are on these? Have you used the Chinese tester? Was it accurate?

The good thing at least all cylinders have the same compression. So either all is ok (compression wise) or they are all doomed.

[Flowers]

First thing that strikes me is those compressions are a little low…

I also noticed that the HT lead and threads of c1 had oil on it, not a massive amount of oil.

Also the car is not running rough after changing HT lead

[g259fsg]

Symptoms sound a bit like the problems I had with the 214. See https://www.rover200.org.uk/forums/topic/15296 . In my case it was head gasket failure on the underside of the gasket between No.4 and the coolant channel. I didn't have mayo, but I did have loss of coolant and pressurising of the coolant system, the same as you. I was looking for the white smoke but didn't get that, however if the car had been standing for a few days, when I ran it there seemed to be condensation from the exhaust that smelled a bit of anti-freeze. Diagnosis using Dr. Headgasket and sniff test with exhaust analyzer at the garage showed combustion gases in the header tank. Initially I got lowish compression readings, but I forgot to hold open the throttle when making the test. When I did that, the compression went from 125 to 140 psi. No.4 was down very slightly on the other three.

Hugh