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Overheating

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Posted: 11-11-2005 08:01 pm

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21^st Post

Sander
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Was that the yellow JH that had been owned by a doctor in Atlanta?

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Posted: 11-11-2005 10:05 pm

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22^nd Post

Rory Clark
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Brett,

I thought that also. But I am getting some overflow into the bottle. What I do not know if it is going back into the radiator. The radiator opening is a little out of shape But...the cap appears to be operational

thanks for the thought.

Rory

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Posted: 11-11-2005 11:44 pm

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23^rd Post

LambandAndy
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Sander,

Not sure if you were refering to me or not but the car looks to have been painted red a number of years ago but was originally mustard. Per Mr. Calvin the car was in Jacksonville, FL in the late seventies. Registered owner since 1993 was in Isle Palms, SC.

I would be interested to find out any more history from the intervening years.

Andy #15223

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Posted: 11-30-2005 02:26 am

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24^th Post

Jensenman
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Rory Clark wrote: Brett,

I thought that also. But I am getting some overflow into the bottle. What I do not know if it is going back into the radiator. The radiator opening is a little out of shape But...the cap appears to be operational

thanks for the thought.

Rory

Be certain the cap is of the 'return' variety; some older caps would, like Brett says, allow coolant to escape when hot but not get drawn back in when cold, and that would definitely flatten the bypass hose as shown in your picture. Since the flat hose is due to 'vacuum' that tells me the main outer seals on the cap are okay. I'd replace the cap with a good quality 'return' style (has a flat brass disc on the bottom that's a one way valve).

BTW, there were about twelve J-H's here in Charleston that I am aware of; a red and a BRG on the IOP, a dark blue one out toward West Ashley, mine, a friend of mine has one running and three parts cars, there was another one with a small block Chevy, same guy had a parts car. A guy left a note on my windshield with a Summerville number a while back wanting to sell me his, and there's the yellow one I missed several years ago.

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Posted: 05-28-2006 11:20 pm

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25^th Post

Joseph Mazurk
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I have a question:::

         What is the oil gauge telling you when the water temp gauge reads past the 1/2 way mark??? I just installed a brand new Dave Bean water pump and a new thermostat and I am leaning just past the half way mark on the temp gauge but the oil pressure is reading about 40 lbs. when engine is warmed up. At first I thought it was the oil pump but when the engine first starts up I am getting 55 lbs of oil pressure. As it warms up and I am driving the oil pressure goes to 40-45 lbs. Any suggestions???

                                joseph mazurk

                                 chicago, il

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Posted: 05-29-2006 12:17 am

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26^th Post

John Finch
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Not quite sure of the meaning of your question but here goes. When the oil gets hot (warm engine) it thins out loosing its viscosity and the oil pressure drops as a result. When you start cold its thicker and you have higher oil pressure. 18309 starts at about 75psi at idle, after running and it gets really hot it will drop to about 35 at idle. My temp gauge is just to the right of center when the back of the thermostat housing is at 180 degrees fahrenheit. The JH manual says 60psi oil at 2500 rpm is normal. I've got about 75 at 2500 if the gauge is accurate. Not sure if this answeres your question. Hope it helps. John

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Posted: 05-29-2006 05:04 am

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27^th Post

Joseph Mazurk
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Hi John,

              Thanks for the reply. I know about viscosity and how it changes when the engine is warm. My engine just started to read 40-45 lbs of oil pressure at 4000 RPMs doing about 70 MPH. Before it was always reading at 55 lbs doing these numbers. I feel very comfortable when my engine reads below 50 lbs. at 70 MPH. I worry that it is the beginning of problems. On a side note I did a compression test and got 125, 130, 130 and 130 with 89,000 miles on the speedo. When the engine starts the oil pressure is at 65 lbs. and when warm does the nose dive to 40-45 after driving it for about 15 minutes. I think this rules out a bad oil pump. So far I am at a loss for a explanation as to why the oil readings are so low. I also disconnected the oil line from the engine and installed a new oil line to a spare oil gauge and got the same numbers. I will check the ratio of water to coolant and add Water Wetter to the coolant.

                                   Joseph Mazurk

                                       Chicago, IL

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Posted: 05-29-2006 05:07 am

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28^th Post

Joseph Mazurk
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Oops, I should have said "I feel very uncomfortable when..."

Joe

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Posted: 05-29-2006 12:44 pm

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29^th Post

John Finch
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Hi Joe, I don't know enough about our engines to go much further other than to agree with you that you might want to stay on top of your oil pump. Is your oil cooler installed? I also run watter wetter and just added water pump lubricant to the coolant as well just to be safe. I hope I didn't offend with the viscosity thought. It was not my intention at any rate. Try one of the Lotus forums. There might be some info there. Piston Heads and Golden Gate Lotus Owners are sites I go to sometimes. Best of luck John

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Posted: 05-29-2006 04:35 pm

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30^th Post

Jensen Healey
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Hi Joe,

So you're saying that the installation of the water pump lowered your oil pressure? It's possible that the new water pump isn't flowing as much water as the old one but that should show up on the gauge. You may have had a coincidental clogging of the oil filter or oil cooler. Have you changed the oil and filter?

Does your pressure go up to 50 lbs at 5000 rpm? If so you are within the Rosenbaum parameter of 10 lbs for every 1000 rpm and should be OK for normal driving.

I hope it's not a sign of worn bearings.

Kurt

JH 13148

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Posted: 05-29-2006 07:39 pm

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31^st Post

Joseph Mazurk
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Hi Kurt,

Could be a clogged oil cooler. This is something I suspect. The fact remains the same, my oil pressure has never ever gone below 50 lbs. at any speed and at any temperature. I might have to take the oil pump off and do Greg's solution to his sudden drop in oil opressure and that is check oil relief valve in the oil pump. Thing is the Eastern J2006 is coming up quick (June 7-10) and I need a solution quick. I do have several oil pumps to switch to if I need to, so I will keep the message board apprised of my progress. Please say a big prayer that it isn't the bearings. Have fun this weekend!!!

Joseph Mazurk

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Posted: 07-29-2006 04:06 am

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32^nd Post

dciaccio
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Joe & All:

My '73 #12248 is in the same condition. The engine temp seems to run up to about the 3/4 point on the gauge or slightly above when the outdoor temp is around 85 degrees and above. Cooler days its just fine. I only have two core radiator which I had cleaned by a local radiator shop. As it seems now from reading all the posts, I probably should have had a three core put in. Joe, my oil pressure is the same. best it will do is about 50-55 psi at cold start but drops to 40-45 psi at 3000rpm when hot. at idle its sitting down around 20-25 psi...little scary. Right now I am more concerned with the higher engine temp. Is it the groups advice to go with the 3 core rebuild ? Any other final checks I should run before spending these dollars?

Thanks

Dave Ciaccio

'73 JH #12248

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Posted: 07-29-2006 04:08 pm

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33^rd Post

Mark Rosenbaum
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Dave:
Your oil pressure at cold start is a bit lower than normal but seems better than average when hot. If your oil gauge is accurate, you might wish to address the oil pressure relief valve if you ever have need to open up the oil pump, but other than that, I wouldn't be concerned.

For the temperature issue, you might wish to consider the possibility that your dash gauge is less than absolutely accurate. Before spending lots of money to fix a problem that may not exist, it would be prudent to actually measure the coolant temperature with a real thermometer. If your cooling system is in good shape it will keep the coolant at the thermostat's rated temperature, or 100°F above the local air temperature, whichever is greater, under normal street driving conditions. For more aggressive driving, this temperature difference will increase significantly, but that isn't a problem unless the coolant starts to boil. If the antifreeze mix and radiator cap pressure are correct, boiling won't occur until the coolant temp exceeds 238°F or thereabouts.

That said, if the cooling system is not performing as expected, you may wish to check the following areas (some of which have been mentioned by others on this thread):

Corrosion in the engine block.
Sediment or corrosion in the radiator.
Mechanical blockage due to debris in system.
Lower radiator hose collapsing during operation.
Insufficient coolant flow.
Radiator cap opens at too low a pressure.
Poor airflow through radiator or oil cooler.
Partially blocked radiator or oil cooler.
Slipping water pump drive belt.
Incorrectly assembled or internally corroded water pump.
Using wrong coolant (needs to be about 30-60% antifreeze). Using water alone will cause your cylinder liners and water pump impeller to rust, and eventual cooling problems are all but guaranteed.
Head gasket leak allowing combustion gas to vent into cooling system.
Exhaust or intake manifold leak.
Excessively lean fuel/air mixture.
Retarded ignition timing. The factory vacuum retard system is known to raise engine operating temperature by about 20°F when enabled.

To improve a cooling system that is known to be in good working order, there are a number of things that can be done. These are:

Using a 'water wetter'. This stuff increases heat transfer to and from the coolant and is probably advisable in any engine with sediment or internal corrosion issues. Such engines frequently have problems with coolant flow or heat transfer that result in localized boiling that gives the impression of an overheated engine.
Installing a late-design Lotus water pump. These are known to have significantly improved coolant flow compared to the JH pump, and seem to help at all speeds above idle. My data is scanty but probably a pump with casting revision E or later would be advisable.
Adding a radiator shroud (fan shroud). This increases air flow through the radiator at all speeds, and is particularly effective at idle. Some care must be used during installation so as to avoid clearance problems and masking of the radiator core. Installation can be a bit tricky because, in a JH, the engine sits at an angle with respect to the radiator.
Adding a radiator with increased heat transfer capacity. This includes larger and/or thicker radiators, those with additional core tubes, etc. Note that a radiator with a larger coolant capacity but the same heat transfer capacity as the stock radiator will not prevent overheating, but will increase the time it takes for the engine to overheat. This may be adequate for street cars that see exuberant use only rarely.
Adding a spoiler. This increases air flow through the radiator if the car is moving but has no effect at all when the car is sitting still. Even a fairly small home-built sheet metal spoiler can provide some improvement. Spoilers can be subject to enormous aerodynamic stresses, and to damage from impacts, so considerable attention to mounting is essential.

In conclusion, there's no black art to solving cooling problems, merely attention to detail and a slight acquaintance with basic physics.

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Posted: 08-06-2006 04:25 am

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34^th Post

dciaccio
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Joe:

I am in the same situation. At start up I get about 50 psi. As the temp gauge climbs up to normal, it drops a bit to 45 psi. As the temp climbs up to the 3/4 point but under the redline, my oil pressure is about 40 psi at 3000 rpm.

I am open to eveyones thoughts here too. Sounds like I am within Mark's tolerable limits of 10 psi /1000 rpm. Makes me feel a little better.

Thanks.

Dave Ciaccio

Omaha, NE

JH #12248

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Posted: 08-23-2006 04:59 pm

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35^th Post

mdutch
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Okay, so any sources for a new Voltage stabilizer for the metering?

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Posted: 08-23-2006 05:05 pm

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36^th Post

mdutch
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              Thanks for the reply. I know about viscosity and how it changes when the engine is warm. My engine just started to read 40-45 lbs of oil pressure at 4000 RPMs doing about 70 MPH. [...]

                                   Joseph Mazurk

Joe,
   I had a similar problem for a while until I was informed that "modern synthetic oil" is too thin when hot to maintain proper pressure. Use good old fashioned Castrol I believe was the consensus. Once I changed the oil from 10w30 Mobil 1 to 30w Castrol, the pressure was normal.

Last edited on 08-23-2006 05:08 pm by mdutch

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Posted: 02-28-2007 03:16 pm

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37^th Post

flatlanderep
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Judson Manning wrote: Mitch,

You might want to install an aftermaket water temp gauge. The stock water and fuel gauge run off a 9V regulator that is prone to failure resulting in higher temp readings when everything is actually fine.

Judson

Judson,
I suspect my '73 JH is suffering from this problem as a new thermostat was just installed but the temp gauge is fluctuating like crazy....One minute it's at the 3/4 mark and then the next its barely registering at the 1/4 mark. Is there a way to test the regulator to verify that it is indeed that, rather than something else?
Thanks,
Paul

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Posted: 02-28-2007 10:32 pm

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38^th Post

Jim Sohl
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The address below is to the Lotus Club of N.Y., N.J. If the address doesn't work, the newsletter is May, 2004. Anyway, the article is about a solid state 'voltage stabilizer' and it appears to be worth a second look. I have not tried the system out as yet, but it sure looks more promising than the original Smith unit.
Cheers,
Jim
http://www.lotusenthusiasts.org/Newsletter/V5-10.pdf

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Posted: 03-01-2007 10:21 pm

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39^th Post

John Finch
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I bought one in Oct 2005 from Edgar Esslinger at esslinger@charter.net on ebay for $20.00. Works great so far. It was listed as a Triumph TR4 Solid State Gauge Regulator on ebay. Try an ebay search. Also, Ed's seller ID on ebay is coolsunbeam

Good luck John

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Posted: 08-10-2008 09:34 pm

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40^th Post

dwalls1
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FWIW Dept.

Since Greg et al convinced me that the temp gauge should never get over 1/2 even after prolonged idle, I've bought and installed the fan shroud. It seems to be the ticket as I can leave the car idle for a long time now and the temp shows just barely over 1/2. The install was not too straight forward even when done in conjunction with the cam belt replacement as I had to have the crank pulley machined off to clear the fan after removing the spacer from behind the fan. (all this is residue from the A/C removal) All in all I'm glad I've got the fan shroud and it looks pretty cool to boot.

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