Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: DreamsOfA47 on Sunday,February 16, 2025, 12:17:45 PM
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Hello all,
I've been away a while but since I posted last I've just been steadily tinkering with my 67S1A and my Type 26 Elan projects. This past Friday I finished installing my new GAZ suspension and drove the car with no issues. Later that evening I endeavored to drive it to a friends house not far from work up the freeway maybe 10 miles. Everything was going well until it wasn't! I have had issues with the cooling system in my 46 before so I'm very careful about checking T's and P's while driving and it felt as if all of a sudden my temp gauge was pegged at 120 C+ and my coolant was boiling out of the swirl pot! I pulled over and shut the car off as soon as I could but damage was clearly done. Now the engine is very hard to start and it won't idle at all nor run below 3k RPM. Interestingly the engine still seems to are you very well above 3k. All my experience as a mechanic has me pretty sure the head is warped and the gasket blown, but do any of y'all with experience with the Renault motors believe it to be anything else? I'm so very sad to have hurt this motor but I need to get it fixed ASAP :'(
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Doesn't sound good. What's the history on the engine? Overhauled? When? Run hot before? What circumstances?
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Ok, I searched your posts and can see that this is a long running issue. Any history on the engine otherwise?
Sure, you could just do a head gasket but the gods might be telling you it's time to overhaul the engine properly.
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How does your oil look ? Muddy? Clean ?
Plugs Clean black or super clean?
Dakazman
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You can have a HG blow into just the cooling system or between just two cylinders and have clean water/oil. If into cooling, a cold engine will pressurize the cooling system, or preserize the cooling and it may drip into the cylinder. Visible with a bore scope. Or if between two cylinders, you will push pressure into them next. Sometimes you will have a knock on a cylinder from being pressurized from it's neighbor. Pulling a plug wire will stop the knock. Leak down testers are cheap, it would be my first check. Picoscope and a pressure sensor will tell a lot but scopes can be a learning curve.
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HI:
A little late now but at some point check your rad.
There is a baffle in the header that forces the coolant to do another pass through it.
That baffle came loose in mine and the coolant just went in and the out again.
The car over heated and luckily I found the problem before the HG blew!
Good luck!
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JB I have no idea the history of the engine. I have no idea when the engine may have last been overhauled or any major service performed. The overheating issues were so loved be the installation of a new rad. It was a cheap Chinese eBay rad but its been working fine for about a years now with no issues keeping the car cool. Bernie I’d be quite surprised if the baffle you speak of would have failed already. Come to think of it, I’m not sure the aftermarket rad I’ve installed has that baffle :confused: Maybe that would be a good thing to check!
Dakazman the oil is actually totally fine and it seems that the cooling and oiling systems haven’t been breached. I haven’t checked the plugs yet but that’ll have to happen ASAP. Clifton at this point I’m believing that I have a break in the gasket or the header has warped such that I have either a breach between 2 cylinders or a breach between a cylinder and the outside. I have a leak down tester at work (I currently work as a mechanic at a shop specializing in 80s Porsche’s) and as soon as I can get the car there I’ll be able to check it out.
Please correct me if you see a major flaw in my logic here: the car was running really well before it overheated. Now that it’s overheated it barely starts. If I can get it to start it won’t idle at all. It can only be kept running above 3000 rpm but above 3 it seems to run pretty well. It’s a little down on power but it revs freely above 3k. I’ve taken up to a little above 4k in a brief troubleshooting stint. All of this leads me to believe it’s not a bottom end or rotating assembly issue. I never lost oil pressure and the quantity and quality of oil pressure seems great. I can’t imagine it would be carb related in any way. I can’t see how overheating would damage the valvetrain either. What do y’all think? I can’t see it being anything else other than head gasket or the head being warped.
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Here are some short videos I took of what the car is doing
https://youtube.com/shorts/Jgd2xHtoXKE
https://youtube.com/shorts/mmNvC-RVG_U
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Why do you think damage was done? Is it hard to start or just hard to roll over? Does it make terrible noises? If so when, while starting, running or both? Is there smoke? Are liquids present in places they should not be?
Remember, white smoke out the exhaust is water in a cylinder and likely a blown head gasket. Blue smoke indicates oil which maybe blow by due to bad or broken rings. It may also be from valve guides.
Hard to roll over maybe due to spun/seized bearings. Hard to start and rough idle below 3k may be due to fouled plugs or timing that is out.
As others have stated, check the easy stuff first, fluid levels and condition, plugs, compression etcetera.
Let us know how you get on.
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Oils any ignition problem cause this? Timing slipped suddenly or something?
I’m no mechanic, but I noticed in your summary of the problem that you have the sequence of: overheating led to barely starting. But what if, while running, something happened (like slipped dizzy) that, if you had stopped right then, would have shown hard starting. And that change led to overheating?
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:I-agree:
I hate to admit that I have had a serious overheating episode in my car (alum. head/iron block) with no repercussions. I realize that such an episode may have different effects in an alum. head/alum. block engine but I think there are things that make sense to check first - including the things Dreamer suggested.
A compression test might be a place to start if you don't have ready access to a leak down tester (I'd argue it would be worth having your own. You can buy one or make one pretty easily (https://www.lotuseuropa.org/LotusForum/index.php?topic=3696.0).
What about your ignition? Is your distributor in good shape (advance weights, point gap if you have them, etc.)? If you have a Pertronix ignition, the attached bench tests might be helpful.
Since you suspect that you have a head gasket issue but your fluids seem fine, put a microphone attached to your cell phone down one cylinder and put compressed air into the neighboring cylinder while it is a TDC (https://www.lotuseuropa.org/LotusForum/index.php?topic=4185.msg44858#msg44858). If the gasket is leaking that way, you will be able to hear it.
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I'm not a carb guy but do your carbs have an idle circuit? Seems to rev fine once it's up there above idle. A nice vacuum leak maybe?
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Go through the basics. Check valve clearances, do a compression test, fit new plugs (common fail point), check the points (replace if pitted) and replace the condenser (common fail point). Check the cap (cracks and carbon tracks) rotor (shorted) and wires (high resistance and cracks in the insulation). Set it all back up and see how it runs. Still poor? Now look at the carb. Plugged idle jets (as mentioned above), fuel supply (plenty of but pressure under 3.5 psi), vacuum leaks (carb base, manifold, cracked hoses).
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Alright y’all I have an update for you! Yesterday evening I managed to get the car to my place of employment to start running tests. So far I’ve only been able to run a leak down test and it showed as follows:
80psi of pressure in
#1 74psi - 7.5% loss
#2 68psi - 15% loss
#3 62psi - 22.5% loss
#4 64psi - 20% loss
This leads me to believe that the engine is pretty tired, but it doesn’t appear to have had the head gasket fail. JB I’m going to start working through your list over my lunch break today. I can start with plugs and we’ll see where I can go from there. Today will be the first I can work on the car with daylight so that’ll make things a little easier. Dreamer and Kendo y’all have both mentioned timing but I’m not sure what overheating could do to affect that, but I may need to begin looking there. Clifton I agree with you it definitely seems like a vacuum leak, which has me worried that the head gasket may have failed between a cylinder and and the outside world, as opposed to into a coolant or oil passage.
I’ll let y’all know what I find!
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Clifton I agree with you it definitely seems like a vacuum leak, which has me worried that the head gasket may have failed between a cylinder and and the outside world, as opposed to into a coolant or oil passage.
I’ll let y’all know what I find!
If it's blown between two, it would still idle but knock when the early cylinder catches the pressure from it's neighboring cylinder. I've had two that did this. Quick test is pull a plug wire. It's not this though as your leak down would have showed it. If it runs good above 3000 rpms, it's not a weak ignition. If I could place a bet, idle circuit or vac leak.
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Alright y’all I have an update for you! Yesterday evening I managed to get the car to my place of employment to start running tests. So far I’ve only been able to run a leak down test and it showed as follows:
80psi of pressure in
#1 74psi - 7.5% loss
#2 68psi - 15% loss
#3 62psi - 22.5% loss
#4 64psi - 20% loss
This leads me to believe that the engine is pretty tired, but it doesn’t appear to have had the head gasket fail. JB I’m going to start working through your list over my lunch break today. I can start with plugs and we’ll see where I can go from there. Today will be the first I can work on the car with daylight so that’ll make things a little easier. Dreamer and Kendo y’all have both mentioned timing but I’m not sure what overheating could do to affect that, but I may need to begin looking there. Clifton I agree with you it definitely seems like a vacuum leak, which has me worried that the head gasket may have failed between a cylinder and and the outside world, as opposed to into a coolant or oil passage.
I’ll let y’all know what I find!
Boy...if I found those numbers in a cold Continental aircraft engine, I'd llet the owner know and sign it off for another year...lol.
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What numbers would you expect from a freshly rebuilt engine? Though I suspect bedding in the rings would improve it.
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What numbers would you expect from a freshly rebuilt engine? Though I suspect bedding in the rings would improve it.
The numbers would change in a properly cared for engine as the rings rotated in their lands in the piston during use as well as the valve sealing, etc. A one-time pressure test (using 80 lbs as a standard pressure) would give you a 'point in time', but not a true average reading, as well as was the test done ice cold after sitting out all night, or after a 2 hours speed limit run down the interstate.
For me (and unless you're blueprinting and expecting it to stay blueprinted past the first 1000 miles) anything more than 85-90% (ie 65-72 on a single test) is not reason for concern, absent smoke, mayonaise, etc and a cut-engine spark plug check by the side of the road. There are too many variables in a complex machine machine (absent catastrophic indications like a connecting rod out the side of the block or metal strewn along the motorway in its wake) to put an absolute stake in the ground around one set of readings; you have to take the whole measure to determine the condition.
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Alright y'all after much more troubleshooting and swearing here's where I currently am:
Firstly the poor running was caused by a vacuum cap that had been knocked off of my intake manifold. The car is equipped with a weber DGV and the nipple that sits directly below the carb on the intake manifold lost it's cap somehow.
Now in regards to the overheating issues I have no idea what caused the initial teapotting of the cooling system, but now the car overheats every time. I'm worried that when I installed my thermostat I may have put it in backwards or it was non-functioning on arrival. At this point I've bled the system several times, even going so far as to pressurize it to ensure any bubbles would be forced out. I've also taken out the thermostat to remove that variable. I'll purchase one of those chemical kits that cage color to check for combstion gasses in my coolant, but at this point I believe that to be what's happening. I'm worried that the coolant is being superheated by an introduction of combustion gasses and the system simply is overwhelmed. Interestingly the radiator in and out hoses seem to be the same temp. Currently I have a new Chinese eBay radiator installed in the car so I don't believe the separating plate has failed and caused the coolant to bypass the radiator as the rad gets far too hot to touch.
I can't really see any other possibilities other than head gasket. any ideas I'm missing, y'all?
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I knew it wasn't a HG and I'm sure you have air in the system. An air pocket won't allow water to flow and your in/out radiator hoses will be the same temp. I had this problem with the top hose at the front of the frame exit. I put a bleed and then finally a 1/16" hose and routed it back to my swirl tank. Not saying that's your air trap but there is air somewhere. They also make a fill kit that uses compressed air to pull a vacuum on the system and fills it under that vacuum. You need to fully drain everything though.
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Alright y'all after much more troubleshooting and swearing here's where I currently am:
I can't really see any other possibilities other than head gasket. any ideas I'm missing, y'all?
Is there any test that will eliminate a head gasket leak? Has anyone used the coolant sniffer tester, are they reliable enough?
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Clifton do you really think that there could still be air in the system? I've pressurized the whole cooling system to 16psi, more than double the systems 7 psi while operating. I also did that with the heater core open so I can't imagine air would have had any place to hide or be trapped.
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Clifton do you really think that there could still be air in the system? I've pressurized the whole cooling system to 16psi, more than double the systems 7 psi while operating. I also did that with the heater core open so I can't imagine air would have had any place to hide or be trapped.
You don't have any HG symptom but the coolant color tests do work if combustion gas enters the coolant. I've used them.
It's not the pressure, any small air pocket will prevent water flowing. I went crazy always burping and trying to get air out of the top line. Until I could get it all out, it would not flow well. It's not just a Europa thing. A lot of mid engine cars.
I don't have a Europa radiator but my radiator top bleed line Tee's in with the outlet on the top of the radiator hose high spot and then go back to my swirl pot. I haven't had to burp since.
Do you have an air bleed on your radiator? Have you checked it recently? Are you 100% sure there isn't a high spot that could have trapped air? Air will not travel back down to escape.
Pic of my setup and a fill kit.
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Just wanted to add. Being that you have removed your thermostat, you should have flow. Radiator in/out being the same temp means you don't. Another reason I think you have an air pocket.
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There should be air bleed valves at the radiator and by the water pump. Pressurizing does nothing to remove trapped air.