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Roberto Giannini
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I was driving yesterday car was running perfect, I always try to look at all my Guages at least once every few min, something I am use to from owning temperamental Ferrari's ;) Car had been running maybe 10 min operating temp was up to normal, all at once I see the reservoir low light come on, I then look at temp guage and it's all the way Hot :eek: I quickly pull over, car was working fine no hiccups at all. I noticed stem rising from back end, got out had a look and there was anti freeze right side only top of engine. I noticed reservoir tank right there looked empty.

After a few min I got back in the car as I could not see where leak happened, I turned car over again temp fell way back down to normal. I drove a few blocks to a Hotel, bought 5 330 ml of cold bottled water, poured them all in waiting for leak but nothing. Cat temp was perfect again. I gingerly drove it home keeping revs low, by the time I got home you couldn't even tell anything ever happened.

Next day we examine and found a 2" crack top of reservoir tank by the pressure cap, it must of let go all at once. I was thinking it was just the pressure cap itself as they tend to do that, but a crack instead ?????

How much pressure do these cooling system produce ? enough to crack a reservoir ??

Has this issue happened before
 

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If you search you will find that it is not all that rare.
 

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Mulholland>SCC
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Yup, it happens. Buy one from Toyota if you don't want to spend $350 from Lotus.
 

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Mulholland>SCC
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Yup, I was browsing on my phone. Didn't realize this was in the Esprit forum.
 

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its a Peugeot 205 GTI header tank; you can get a Peugeot style alloy tank from Baileys out of UK; there's a Moroso alloy tank that can be adapted to fit on the inside rear fender well.
 

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Just looked at the parts manual, it is 20PSI (140kPa) on the V8.

On the SE it is a 15.9psi (110kPa) pressure cap for the coolant and 7psi for the chargecooler. And the S4 and S4s with the plastic tank is also 15.9psi (110kPa).
Just checked my manual. In the V-8 Technical section, page 6, 1/2 way down under cooling system, pressure cap, it says 1.1 bar-15 psi.
If you really do have a 20 or 21 psi cap I would replace it immediately before you blow something up.
David Teitelbaum
 

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Just checked my manual. In the V-8 Technical section, page 6, 1/2 way down under cooling system, pressure cap, it says 1.1 bar-15 psi.
If you really do have a 20 or 21 psi cap I would replace it immediately before you blow something up.
David Teitelbaum
Hmm, the V8 parts manual says 20psi, but I thought for sure I remembered 15psi for the v8 as well.
 

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Pressure spec for the V8 per the workshop manual is 15.948491284586439 psi

For the four banger is 14.384857382934858504 psi.

Or, you can just put a 1.1 bar cap on it and be done with it.

ps. yes, the tanks crack and split. It has nothing to do with the pressure spec, has everything to do with the plastic aging and becoming brittle.
 

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Lotus Service Notes. Section TDJ. Page 8.

"Pressure Cap - 4-cyl Engine 110 kPa (1.1 bar; 15 lb/in)

V8 145 kPa (21 lbin)"


There was a change. I have from reputable sources.

Also. The parts diagram on Lotus Garage lists a 20 lb cap for the V8.
 

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Lotus Service Notes. Section TDJ. Page 8.

"Pressure Cap - 4-cyl Engine 110 kPa (1.1 bar; 15 lb/in)

V8 145 kPa (21 lbin)"


There was a change. I have from reputable sources.

Also. The parts diagram on Lotus Garage lists a 20 lb cap for the V8.
My section TDJ 1997/02 has it on page 5 at 15 psi. My previous post was out of section TDK V-8 specs. 20 psi is a BIG difference from 15 and this should be verified as to when it was changed and which cars it is appropriate for. Most radiators can't handle that kind of pressure. My parts manual just gives a Lotus part #. No pressure specification. I will retest my pressure cap to see what it pops at to see if it is 15 or 20 psi.
David Teitelbaum
 

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My Section TDJ is dated January 2004. If I remember correctly each 1 lb of cap pressure raises the boiling point about 17 degrees. Don'y quote me on that! It should go back to that old chemistry formula of PV=NRT (Boyle's Law?). Probably was changed to prevent boiling the coolant in the turbos under high use. (Again, don't quote me on that either. Just a guess.) I've had the original 21 lb. cap on the car since new and for the current 85,000 miles. Haven't blown anything up because of it yet. The reliable source is some knowledgeable - recently retired and to be missed - common vendor.

Later Note:

I thought I'd check the Owners Manual. On page a62 of the manual with the date 2002 on the face page the specification is given as follows;

"The header tank is mounted at the right hand rear of the engine bay, and is fitted with a 110 kPa; 15 psi (4 cylinder) or 145 kPa; 21 psi (V8) pressure cap to raise the boiling point of the coolant over 100 deg. C"
 

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Just got a chance to check the owner's manual. It gives the specs for the 4 cyl and the V-8 although it is a '99 V-8. The pressure rating IS 21 psi. Checked the cap and it is stamped 145 Kpa which is 21 psi. Pressure tested the cap and it is around 21 psi so I am guessing but the 4 cyl's are 15 psi and the V-8's are 21 psi. Lotus used a lot of the literature for the 4cyl and modified it for the V-8. They may not have gotten it right and properly modified in EVERY spot.
David Teitelbaum
 
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