hi all,
since i put my series 3 4.2 on the road its been hard to start after taking it foir a run then stopping for a reasonable amount of time, eg over twenty minutes. in the time its had a new fuel pump, filter, leads, coil ect but always had the hot start issue. i was banking on it being a weeping injector until today i had the intake piping off and had a look down the throttle body only to find green coolant in there!

im assuming its a crappy intake gasket but am wondering if anyone else has experienced this. the car starts first time every time cold, it never takes more then a few rotations to fire up when cold but when hot it takes at least te seconds of cranking.

thanks,
jay

 

A leaky intake gasket seems the most probably culprit.

Do you have a cooling system pressure tester? If so I'd be tempted to pressurize the system and then peer thru the throttle body, looking for drips or trickles.

Less likely is a leak in the manifold casting itself allowing water to migrate from the coolant rail area into the actual intake area.

The throttle body itself has coolant passages. Some investigation there might be in order.

This is an odd situation. Let us know what you find

Cheers
DD

 

i dont have a pressure tester but i know the coolant was fresh in there because it only had water in the engine until earlier that day when i did all the hoses. i was doing the throttle body water hoses and a few fuel hoses when i noticed how filthy the throttle body was and took a look down only to find water!

there is a bit of corrosion in the cooling system so im worried it could be a corroded manifold. the welsh plugs down there didnt look all that good so im thinking ill remove the manifold and replace the plugs, clean all of the efi stuff up (air bypass, throttle body ect), take the dizzy off for a service (there is a little corrosion in there).

im tipping its a job best done on a hoist so i can take the bottom nuts off the manifold?

is there anything else i should do while im in there?

Thanks,
Jay

 

Just to verify.......

Earlier you said green coolant in the manifold. Here you say water. Which is it?

Some water in the bottom of the intake isn't unusual. It's condensate from the breather system. There's a capped-off nipple at the bottom of the manifold to drain it off as needed.

Actual green coolant is a different kettle of fish. Shouldn't be there at all.






A hoist is great but you can reach all the intake nuts from above. You just have to reach under the manifold and undo the center ones by feel.

Freeing the manifold from the cylinder head can be a monumental chore. I use a small bottle jack from multiple angles/locations to help push the manifold off the studs

Cheers
DD

 

sorry for the confusion, its actually a mixture of water and green coolant because i only put green coolant in earlier the day i noticed. it had water in it for the past year because i didnt want to put coolant in until i replaced the hoses. i was in the process of replacing the last few small hoses after the car had been for a run when i saw the coolant that had obviously leaked in there when the car warmed up. the system does hold allot of pressure and has a 15psi cap which seemed high to me?

ide imagine the hard hot starting is caused after the manifold is flooded with coolant and steam, it seems odd that it starts at all to be honest with the amount of coolant i could see just under the throttle body! its an issue that you would never think of looking for and if i hadnt put coolant in there i would never have found it either.

the other thing worth noting is when i got the car it never had a hot starting issue, it only developed after i registered it and started driving it on the road, which i assume is because it never got hot enough to spew coolant into the manifold. it starts strait up if you stop it hot then try to start within a few minutes, its only when its been sitting for a period of time, eg half an hour - an hour that it is hard to start.

thanks,
jay

 

There is another path for coolant to enter the inlet manifold. Does your car have the vacuum operated heater valve ? It has been known for the diaphragm to fail or start leaking, whereupon the vacuum draws coolant into the vac lines and it ends up in the inlet manifold. Having said this, the case I read about was a Mark 10 with a similar valve, so this may not apply on your car. And, of course, it has to have the heater valve anyway.

 

Fraser....good point ! And a heater valve is a much easier fix than a manifold gasket.

Cheers
DD

 

I think it would be reasonably easy to check on this. Just remove the vacuum line by the valve and see if the passage is at all damp. OR, clamp off the vac line to the valve and see if the problem goes away.

 

With water ONLY in the cooling system for a year you might have created your own problem with corrosion.

Antifreeze solution has corrosion inhibitors to prevent this sort of thing.

A complete 'manifold-off' inspection might be necessary to look at the manifold-to-head gasket as well as the water rail areas.

bob gauff

 

we all know how it goes, i was waiting to put coolant in the system until i replaced the hoses which i didnt get until last week as money is of the essence, so i may well have shot myself in the foot there! however, the problem has probably been there most if not all of the time coolant wasnt anyway. there are several bits of the cooling system that look corroded so ide say its through many years of neglect, not just my one.

i wouldnt expect a manifold gasket to last much over 30 years regardless of weather it had coolant or not, although as has been suggested it could very well be part of the manifold corroded.

i will check the heater tap although im pretty sure its the aftermarket variety that the diaphragm is joined by external linkages.

ive also heard that removing one of the welsh plugs or plates is a good idea and flushing the back of the block?

thanks,
Jay