Esprit Models
Esprit History
For Sale
Other Stuff
Buying & Running
Parts & Specialists
Other Esprit Stuff

Radiator & Oil Coolers

LEW's SE gets a new Rad and Oil Coolers at SWLC

With our engine being rebuilt due to wear, there was high levels of Lead, Copper, Silicon and Sodium in our oil samples. Which meant our oil was contaminated and needed cleaning out. It isn't really possible to flush the oil out thoroughly enough to make sure all the contamination is removed and won't continue to damage your engine. It is possible to remove the oil coolers and acid bath them, but removing Esprit oil coolers is a real problem. Connections are weak and with corrosion, rarely undo without breakages.


Our oil coolers didn't survive being removed, so some new verions were sourced by SWLC. These are slight upgraded versions, that look great as well. We'll soon see how good they look after a few thousand miles of English weather.


This job could be done by owners, but is a little involved and as the chances of damaging the coolers is high, you could leave yourself 'high & dry'. We'd advise something like this is done by your local specialist.

We'll update this page with some more info on our oil coolers once we have it. You can always call SWLC who performed the work on our Esprit.

This work was performed by SWLC on LEW's 1992 SE


The story continues!

With our oil coolers needing to be removed to make sure all the contaminated oil was removed. It was only sensible to have a look on the condition of the Radiators. Esprit radiators are well known for being really labour intensive to remove and replace. The Rads themselves last ok and aren't too expensive, but the labour turns this into one of the most expensive jobs on an Esprit.


SWLC checked out our Radiator once the oil cooler were removed. This was a good time to get in and have a look and do anything that was needed, as the labour costs would be reduced. Unfortunately the radiator was found to be in pretty poor condition and really needed changing. There was plenty of debis that had blocked large parts of the rad (see article below) and corrosion had a good grip.


SWLC removed the old rad and replaced it with a V8 version. This type of work, along with the oil coolers is something that in theory is possible for owners to do. But with the radiators, access is very difficult and some nuts and bolts will be seized and will need cutting off. Work like this is very difficult with a lift and we would advise anyone other that an experience home mechanic to leave this sort of work to the specialist like SWLC.


This work was performed by SWLC on LEW's 1992 SE

Radiator Debris
Are leaves and dead bugs reducing your cooling?

We summer just about here and Esprits taking to the hot and sticky tarmac, the worry of overheating if you get stuck in traffic is always at the back of your mind. It's worth regularly checking the fans are working and making sure you're fluid is topped up and changed regularly. One other thing to watch for that could give you problems in the hot weather, is debris stuck to the radiator.

This can effect new as well as older models, and with the Esprits radiators being low and with a small surface area, it can affect the cooling dramatically.

Below are a few pictures of the Engineering departments Esprit radiator, the car's currently being prepared for a slow moving precession that Lotus are supplying cars for. The bugs/debris is the route cause of many over heating problems and the reason why Lotus specify the cleaning of radiator finnings at A & B Service Intervals (see below).

In these pictures you can see the bugs/debris is restricting the air flow through the radiator at least 30% and will rapidly cause overheating in slow moving traffic, coupled with hot weather is a recipe for disaster. The best method to clear the debris is blowing through the fins from the exit side using normal workshop air line pressure whenever the Esprit is in for any work.


V8 Radiator Update
From the News pages of LEW, August 2005
Bob Metcalf from Philadelphia PA USA wanted to share this with users. Bob has a 98 V8 which he purchased new. This car has been driven and now has 51,000 miles on it. For some time the car had been running hot, never overheating but hot (110 stuck in traffic). Bob did all the usual stuff, water wetter etc. Anyway a couple of weeks ago his radiator started to leak and he had to get it replaced. This picture is what came out of his car. It's a wonder that it could run at all without overheating. This picture might be instructive as to how bad it can get so that other Esprit owners could be on the lookout for what obviously is a serious condition.

Information from Lotus
This radiator issue mention above is something that Lotus have been aware off for some time and there is a specific item in the Lotus Service Schedule. Under Cooling System the following instruction should be noted.

Inspect radiator, oil coolers & pipework for damage or leaks. Clean all radiator finning.

The radiator fin cleaning was introduced for the reason we see on the failed radiator picture - the core blocked with road debris. According to the Maintenance Schedule - USA Esprit V8 (Section OF in the Esprit Service Notes) this operation should be carried out at every Service.

If this operation is not carried out there is a high possibility that the engine will overheat. This is typical of the kind of thing that can lead to failure of the Cylinder Liner seal.

Updated 06.01.2009

Is your V8 Cold inside?
Esprit V8 Heater info from Lotus Engineering
Just before Christmas Lotus had some trouble with the Heater performance on their 2002 V8. Just thought we would let you know what we found as it might benefit other owners.

The Heater performance had dropped significantly which really only showed up when the cold weather arrived. (Brian nearly froze on a trip to Newcastle when the outside temperature was down to nearly zero!). Lotus Engineering checked the basics (inc. water valve control & operation etc.) and thought they may have a partially blocked heater Matrix.

As this is about the worst job on an Esprit they decided to check more thoroughly before they decided to tackle this. They flow checked the heater system and confirmed that the matrix was clear and the water valve function was normal but the heater was struggling to generate any significant heat.

A thorough check of the system revealed that they had a defective Diverter Valve in the Cooling System. If this Valve is not switching the hot water can bypass the heater matrix. The valve internals were sticking and not allowing the Vacuum to fully switch the valve position

The Valve is Vacuum operated and was not switching 100%. (The vacuum signal was getting to the valve connector). Changing the valve cured the problem and now the heater is generating enough hot air to burn your legs! If any owners are experiencing poor heater performance we would advise them to check the Diverter Valve. The Valve and the Cooling Circuit are detailed in Section 18.05 of the Service Parts Book.


return to top
home email news esprit models road tests buying an esprit running an esprit esprit owners maintenance pictures for sale history Lotus models links