Ever since a pro-workshop carburettor overhaul (new floats/needles/seats/gaskets + tuning) almost 3 years ago I am still getting these white spots on/around the front carburettor. After wiping them off new ones always reoccur when returning from a new ride. Could this be excessive fuel squirting/flooding from the carb system? The 3.4 engine runs smooth and strong with an average 98 octane/non-lead fuel usage of 1.2 litre/10km (23.56 UK mpg). However when speeding down after cruising for some time at +/- 90 km/hour I often sense a strong gasolin smell from within the car, even with the windows shut. The workshop looked into this issue last year concluding the spots may come from an untight water hose so they, well, just tightened it... Still, to me these pictures strongly indicate that the leak IS coming from the carburettor system? Grateful for any opinions, Cheers.

 

Gasoline doesn't usually cause white spots like that on aluminum, coolant does.
The transmitter right by your thermostat housing should not be green, check that area for coolant leaks and cracks.
You may also want to remove your thermostat and check that area for small cracks. Look for corroded aluminum where the upper rad hose isn't sealing well _ check to be sure the thermostat gasket mating surfaces are clean and un-damaged.

The gas smell could be a simple float adjustment needed _ start with that.

 

Could be float adjustment, but here in the US, the ethanol fuel creates conflicts with the gaskets and they need renewing occasionally.

 

The spots do look like water/Coolant - not fuel. I am thinking that your fuel smell and the spots are unrelated issues.
Lin

 

I agree with all re: the spots but suspect from the pictures the fuel smell may be from the aux. starting carb. Looks like a lot of questionable work in that area and one wire looks as if it may foul the plunger.

 

Thanks everyone. It is probably time for a new thermostat/gaskets anyway, and I will check the housing/hoses for cracks and leaks as well. And George, I will definitely check/relocate this cable away from the plunger.

 

Something else doesn't look quite correct in that circled photo either, but it's hard to tell.
The metal "tang" that's used to keep the adjustment screw from turning doesn't appear to be doing it's job, it looks like it's turned away from the screw.

 

Jeff is spot on, also check the heater hose connections, it looks like there is a small leak somewhere that is either spraying out, or a drip that is being being thrown back by the fan, as the marks look more like water being sprayed somehow either by pressure or by air.

Let us know what you find.

 

JeffR1, are these the adjustment screw + metal "tang"?
TilleyJon, though the stains probably come from water, I find it a little peculiar

that a random coolant spray/squirt will accumulate like this at the bottom of the front carburettor..?

 

Those white deposits at the base of the dashpot (bell shaped chamber) are definitely not fuel. Besides there is no liquid fuel (only vapour) that would leak out of the dashpot. IMO the accumulation is due to water/coolant/glycol antifreeze, whatever, collecting at the base of the carby.

Is the car losing coolant to the extent it requires topping up often?

 

coolant.

 

Statfunk, I see the metal tang in your new photo _ nothing to worry about in that respect.

 

OK, so from now on I will definitely forget about an improbable fuel leakage and rather focus on cleaning op and servicing the thermostat area :-) BTW, during 3 years I have never noticed any coolant loss or overheating issues.

 

Could be road spray- do you drive on wet gravel roads? But you would probably see it in other areas not just the carbs.

 

I would say it's leaking in this area, but I would not dismiss where the sending unit seals on the housing.

 

Hi again, over 4 years have passed, so it is in due time for an update.
Car is still running fine, yet still occasionally squirting - and now even slow dripping coolant when engine is hot.
Last year/spring the engine started heating, the temp gauge soon crawling past 70 and approaching 80 when queuing for a
few minutes. Then steadily falling back to the normal 70 mark very soon after getting up to constant +60 kph. running speed.
My workshop decided to replace the thermostat to a lower temp. rated one, and also changed the coolant to a pink/red type.
The new thermostat house gasket looks dodgy to me (possible an improvised rubber cutout + Tek7..?),and I noticed pink/red
drops leaking just a few days after, i.e. same color as now and then squirting around. The temp gauge has never since
exceeded the 70 mark, though.
I have inspected/photographed the thermostat house from underneath. Parts of that area seem to suffer from (bad?)
aluminum corrosion. And the water pump bypass hose seems to be clogged at the manifold water inlet pipe end, showing a
"bulge" just before the hose clamp, plus some nasty “stuff” mushrooming on the hose edges. My +7 years workshop went
bankrupt this spring, so where should I start on this issue?
- Changing the bypass hose, looking for aluminum oxide sludge?
- If so, eliminate all visible physical "crud & stuff," then thoroughly flushing the engine block/waterways?
- Inspecting/changing the water pump?
Any ideas on possible causes + further suggestions on how to start and proceed are of course very welcome.


3.4 engine

Red stains carburettor

Coolant dripping on distributor

More coolant dripping

Thermostat house leak after thermostat replace job, possible dodgy/non-standard gasket?

Thermostat house "gasket" seal, underneath

Blocked(?) water pump bypass hose entering water inlet pipe

Coolant dripping on distributor cap and steering rack

Coolant seeping out and dripping from water pump bypass hose clamp

 

The last photo shows quite a leak from the hose itself because the clamp appears to be over tightened and is cutting into the hose.
It's probably overtightened to try and compensate for all the corrosion on the aluminum fitting.

If this was my car I would remove the rad and expose all the hose fittings in that area _ repair or replace as needed _ replace all the hoses too.
The thermostat face on the car may need resurfacing along with the thermostat cover.
Who knows what you're going to find when the coolant rail on the intake manifold is removed.

The large bulge in the hose is shot _ needs replacement _ and the fitting that it goes onto looks very corroded, that needs to be dealt with too.

Also, is that red coolant compatible with aluminum ?

 

In the era of aluminium radiators Etc. Etc. all coolants will be compatible with aluminium & relatively fungible with one another although I do NOT recommend mixing. You can cause gel formation over time. Good enough to drive home after a burst hose or whatever.

I would give the system a Citric Acid flush (available at your local Benz dealer for peanuts) followed by a good flush with tap water & refill with a good OAT or HOAT longlife coolant.

Replace all suspect hoses & clean & reface if necessary all gasket surfaces starting with the thermostat housing interface.

You might have to have the bypass manifold tube welded & refinished. They corrode badly on cars that were neglected at some time in their history and are not available new other than for the E Type.

Good luck

 

I agree totally with Glyn on his recommendations
That hose is "shot" and I would not drive around the block with a hose in that condition.
It may have been the instigator of the original problem of the surface spots (corrison?) on the carbies. A general weep back from the hose? Who knows?
Bill Mac
MK1
MK2
S3 XJ6
X300
Previous about 12 other Jags

 

Thanks for your response, here is my post-repair update;
The root problem was indeed the badly corroded aluminum pipe that connects to the bypass hose, ref. before/after pictures.
Luckily all pipes are internally clean with no crud/sludge buildup, so circulation should be fine. I replaced both top hoses,
removed all the powder-like aluminum oxide with a steel brush, and used a metal epoxy clay (type JB Weld SteelStik)
to carefully plumb and rebuild the damaged, porous and in some areas perforated bypass pipe.
I have driven 400 km since last week´s repair, and the previous coolant dripping/squirting problems are now all gone.
I think/hope this repair will last some time, as this metal epoxy should take heat, moist/pressure and the red Longlife coolant.
Finding a usable Mk2 3.4 inlet manifold water pipe is not easy, and I believe no parts vendors offer these as remake spares?
Before/after #1

Before/after #2

Before/after #3

Water pump + upper radiator