Silber

I suggest going with the R888Rs if you want to maintain a grippy tire in the same size. Another option is moving up to 195 width tires which opens up a couple of Falken tires that would both be adequate replacements for your Star Specs.

I also participated yesterday and today in a two-day charity car show in the town I live in. Last year I had to choose between the Utah British Field Day event and this one, but to my benefit British Field Day is next weekend so I will be able to attend both. Mostly classic American cars, but I had a nice neighboring Austin Mini and a Midget a couple of cars down that brought a British vibe to our side of the show. Imagine what it would be like if all cars were about this size, instead of the 8000 lb behemoths that are commonplace nowadays.

My friend's shop was home to some lovely cars. I only took pictures of the two that were in the shop, but in addition to the Bugeye Sprite and 914 below, there was also another Bugeye, a first gen Camaro, a Nissan Skyline GTR R32, and a nice E36 M3 sedan.

Overdue for an update. Spent a bunch of time working on the cooling system, which you can read about in this thread. Long story short, the car runs a little hotter than I would like, but the cooling system seems to be operating correctly. Once that was sorted, it was time to get the suspension dialed in and some new tires (finally!). A friend of mine offered to help me do a string alignment at his shop and mount my new tires, so I loaded up to drive a couple of counties over to where he lives. I saw at least one person taking a video of me driving down the interstate like this We were able to fairly easily get the specs I wanted. End result! Decided to go with -2.0 degrees of camber in the front, -1.6 degrees in the rear, and zero toe all around. As mentioned in an earlier post, the intention with these specs is to try and dial out the understeer. Initial drives show little change on turn-in characteristics, but the front end has more grip once the suspension is loaded in a corner. I'll need to take it to an autocross to really tell, and I'm excited about the new tires as well. I went with Kumho V730s, 205/50r15 front and rear. I love the nearly semi-slick look, and I think they will be much better than the Bridgestones from 2018.

From what I've seen the thermostat is integrated into the housing, so the whole housing is replaced. It sits on the left side of the engine near the front, and is thankfully really easy to replace. It's more work to drain the coolant than replace the housing. 210-215 °F is still safe, but my preference is to keep the coolant temps closer to 200. Maybe I'm fretting too much over 15°, but I can imagine that in 95° heat cruising down the 1+ kilometer front straight of my local track I will probably see even higher temperatures. Yes on 50/50 coolant and a pressure cap.

Due for an update. I finally got around to working on this problem. Here's what happened: Removed and tested the new thermostat along with the old thermostat in a pot of boiling water. Both thermostats were functional. Re-routed the system to eliminate the heater core, capping the bypass on the thermostat housing. Removed the heater and covered the holes. Removed the thermostat out of the old housing and reinstalled to allow full flow. Flushed the system with water two times. Reinstalled the new thermostat/housing and burped the system. The result? Mixed and dissatisfied. Everything seems to be working, but this thermostat keeps the system between 210-215 °F, which is hotter than I like. Stayed in that range on both the drive to work (47 °F ambient) and the drive home (68 °F ambient). I'm not confident it'll stay that way when it's 90+ in the summer, or during track/autocross. Positives: the car warms up faster and warms up regardless of the car being stationary or in motion, and removing the heater has reduced footwell temperatures, which will be very nice in the summer. I'm considering trying another standard replacement thermostat from the local parts store, or even trying a lower temp thermostat like this one.

That makes sense. Simplify and add lightness, right?

Pinching the thermostat → heater hose is easy enough. I'll give it a try. I believe the indicating temp sensor is coming off the connector between hoses 2 & 4 per your diagram. There is another sensor directly in the manifold. I plan on testing the thermostat. I appreciate everyone's feedback. I'm going to try MV8's suggestion to pinch the one hose to the heater first just for another data point, but after that the plan is to: Tear into the system again and remove the thermostat and heater Test the thermostat and depending on results install it again, install a new one, or install a modified housing that allows constant flow Properly flush the system instead of just drain and fill I remade my diagram to hopefully make it easier to read. First picture is the current system, second picture is how I plan to bypass the heater.

Looks like I'm going to be re-plumbing the system because I'm left scratching my head about this cooling system. I did not get the thermostat to open at all while the engine was running today. I started off running the engine with the expansion tank off, rear of the car raised. I saw a bunch of bubbles in the expansion tank, but the thermostat did not open at 180 F. The radiator fan kicked on at 190 again, and I confirmed it is spinning correctly drawing air through the radiator. The lower coolant hose was cold when I shut the engine off at 210 F, at which point coolant started bubbling up out of the expansion tank. I put the cap back on, and found that some hot coolant flowed through the lower radiator hose. What? Started the engine after a few minutes, 190 F, rear still raised and expansion tank cap on. Lower radiator hose cooled off with airflow from the radiator fan, and stayed cool when I shut the engine off at 210 F. I started to relieve pressure from the expansion tank cap, with my hand on the lower radiator hose, and as I was relieving pressure I could feel hot coolant flowing through the lower hose. I don't understand what is going on... is the thermostat opening only when I relieve pressure in the system? Left the car for a few hours and tried one more time. Expansion tank cap on, car flat on the ground, the thermostat still did not open. I opened up the expansion tank while the engine was running at 200 F, no flow through the lower radiator hose, but I did notice some more bubbles, so I raised the rear of the car and let it burp for a few minutes. Put the expansion tank cap back on, shut off the engine, and no flow through the lower radiator hose. Relieved the pressure in the tank and felt the coolant flow again. So my thoughts are that I've got a faulty thermostat, or this system is very difficult to burp/bleed and is really causing flow issues, or some other problem yet to be diagnosed. I did, however, find that there is another bypass that I had missed that runs from the engine block just behind the thermostat housing to the manifold on the back of the engine. Everything on the right side of the diagram I posted gets properly hot, the upper radiator hose gets fairly warm, and the radiator and lower hose remain cold.

Not going to be able to get to working on it until Friday at the earliest, but here's the plan: Prop up the rear of the car and allow engine to warm up enough to open the thermostat and run the fan. Purpose is to see if the system will burp and operate normally. If Step 1 does not result in normal behavior, drain and flush the system while also changing the routing to bypass the heater completely. The fan switch for the heater doesn't work, and I don't drive the car in the winter due to salted roads, so removing the heater was already something I was considering. Repeat Step 1 with the new routing and flushed system. I'll report back here with my progress.

It also looks like the Zetecs have a different location for the thermostat, at the back of the engine instead of next to the water pump.

The thermostat housing is on the front left side of the engine, and the small hose from that runs to the heater. The small line from the expansion tank runs to the manifold on the back of the engine. I made a new drawing with a different program that should make it more clear. Looking at the other drawings, it appears that expansion tanks typically have a third hose for a breather. I only saw two lines coming from the tank, so I'll need to take a closer look tonight.

That's the thermostat. My system looks fairly similar to the Duratec diagram, but the bypass from the thermostat goes directly to the heater core, and the expansion tank is in a different location.

Here is a really quick drawing of the layout of the system: Black box on the right is the heater core. The bypass from the thermostat goes to the heater core. The "t" on the manifold on the back of the engine also has a sensor in it, not indicated in the drawing. Only spot to burp/bleed is the expansion tank. The line you are referring to on the expansion tank goes to the manifold on the back of the engine. I plan on renting a pressure tester. I'll keep the vacuum method in mind if I don't feel confident the system can be bled through burping. Thanks for the link. The advantage is I already have 4+ gallons of green, haha! I'll stick with the G-05 for now, and plan on doing a proper cleaning/flush of the system if problems persist. I'll report back on progress when I get back to working on the car this weekend. Thanks for the responses everyone! My conclusion is that there is a solid chance that the system just simply needs to be properly burped, so I'll start with pressure testing the system and burping with the rear of the car raised, while also verifying that the radiator fan is spinning the right direction. If the car is still exhibiting the same behavior of long warmup/insufficient cooling at operating temp, I'll proceed with cleaning and flushing the system.

1) The car has a standalone, F.A.S.T. XFI 2.0 2) Interesting idea, and could be valuable to have a visual confirmation of what is happening if the issue isn't resolved . 3) There is a heater core (sitting under the brake/clutch reservoirs), but I'll look into that tool. 4) Agreed that a pressure test would be prudent. 5) I have a similar large funnel that I use. I guess the Caterham radiators are smaller? You would think with a large radiator the car wouldn't have a hard time staying below 215 degrees... Low hanging fruit for diagnosing the issues appears to be making sure the system is properly burped. I'll try jacking the car up in the rear to guarantee that the expansion tank is the highest point. Using an older picture, I am only trying to burp the system from the expansion tank. I haven't noticed any other bleed valves, but could easily be missing something.