Hot Engine - not cooling properly

[Andy_J]

The engine on my project car does not seem to want to cool properly, and I am running out of 'cheap ideas'

The car runs and drives, but after about 15 mins of driving the engine temp rises up to 3/4 when the fans cut in, it will then hold the temp at 3/4 at idle with the fans cycling on and off (not driven the car yet once the temp reached 3/4, I stop as I dont want HGF)

So far I have checked the following
1. coolant is fine and is not dropping (No leaks of HGF as far as I can see)
2. Replaced, then removed the Termostat
3. Flushed radiator & engine
4. no visible blockages in the radiator fins

The car has 155K miles and aircon (Aircon radiator sits in from of engine radiator) and is missing undertray for the radiator

Andy

[Monty]

What happened when you tried without the Thermostat?

Maybe do an Elan Scan to make sure the temp readings are correct


Are you getting alot of bubbles/pressure in the coolant tank? Might be worth doing a block test to make sure that there`s no combustion fumes getting in to the coolant.

[Andy_J]

What happened when you tried without the Thermostat?

Maybe do an Elan Scan to make sure the temp readings are correct


Are you getting alot of bubbles/pressure in the coolant tank? Might be worth doing a block test to make sure that there`s no combustion fumes getting in to the coolant.

Without the thermostat the car reacted the same, just took a wee bit longer to 'warm up'

Don't have access to elanscan at the moment, however the engine seems far hotter than my green elan

Doesn't seem to be any bubbles or excessive pressure in the coolant tank, will get a block test done once it stops snowing

Andy

[theelanman]

what sort of condition is the rad in???......
just wondered if it may have spung a leak at some time and been filled with good old radweld......or something like that

just a thought

[Andy_J]

Radiator is rusty along the bottom, but looks in reasonable condition, There seemed to be a good flow through it when I flushed it, and ran clean very quickly

[BFG in the BRG]

Only things I can think of is if you are able, check how hot the rad surface is - in case the matrix is blocked (as per Elanman - Radweld/rust etc) it may still appear to run freely is the ends are clear. Other than that - water pump - possibly not circulating properly - mind you I would have thought the temp guage wouldn't register - I still favour the Radiator.

Are all the rubber pipes throughout the system hot and the same temp - I would expect the output side to be slightly cooler (possibly)?

[Andy_J]

I was thinking either radiator or water pump myself, however, it is a little more difficult to check the main radiator as the airon radiator sits infront of it and the gap between the two is only about 10mm.

I have done a block test, and that came up negative (no combustion gasses in coolant).

Whist I was out doing the block test, I tried an experiment. I took the radiator undertray off my other elan, poped it on this one and went for a run, Interestingly it seems to have some effect, at 60 it kept the temperature below 1/4 and round town the temp was varying between 1/4 & 1/2 depending on speed.

This seems to imply a radiator problem of sorts, not sure though if it is the aircon radiator blocking air flow to main radiator, or if I have a problem with the main radiator. Think more testing is in order

[ailwyn]

Might just be me and my simplistic outlook, but doesn't this point to an airflow issue, and the need for a rad undertray??

Presumable the lack of undertray is allowing the air to run under the radiator (path of least resistance), not through it?...

[Andy_J]

Having tested it with an undertray fitted, that does seem to be the case, I am a bit surprised how much of a difference it makes, as I have run non-aircon elans without the undertray and they seem to cool properly

[surfboardfiller]

Having tested it with an undertray fitted, that does seem to be the case, I am a bit surprised how much of a difference it makes, as I have run non-aircon elans without the undertray and they seem to cool properly

Why do you think the put them on? Did you take the lip spoiler off as well?

[Monty]

I`m sure Dico removed his undertray years ago and never replaced it and has no effect on his temperature gauge, besides it certainly wouldn`t run at 3/4 with it off.


If you are getting a correct reading then maybe remove the rad and give it a good clean, but would have to be pritty bad to get such i high reading whilst on a normal drive. so maybe it could be the pump blades have rotten away

worst case could be a build up of rust deposits on the headgasket blocking the water passage

all guess work lol

[surfboardfiller]

I agree, The car would still cool when not moving, did you check both fans working, and the engine not running lean? That would increase engine temperature and be easily diagnosed with an emissions test.

[Andy_J]

Think I am going to get an under tray and give the radiator a good blast with the pressure washer to ensure the vanse are clear.

If that does not work i guess it is either a recore on the main radiator or a new water pump

[muley]

I'm guessing water pump - a local LECer took his pump off and there were virtually no vanes at all! But cleaning the rad externally might be worth doing, but on an airconned car I think the aircon rad will collect most of the crud. Unless the water rad is corroded badly.

BTW I've run my airconned Elan for a while with no undertray largely because it wasn't on there when I bought the car - it had no lip either but that was quick and cheap to replace..

Rgds

Jim

[Andy_J]

Cheers Muley, as the car has 155K miles on it, and i don't think the pump has ever been done, I guess the vanes could be shot, just trying to avoid having to pull the cambelt, etc off as it is a bit of a git to do

[Ade]

Just a thought, could it be an air lock in perhaps the heater pipes.

[PECKHS]

hi andy_j,

i know this thread has been idle for some time now, but did you manage to find what caused the engine to overheat? i'm having the same issue with my new purchase
tks

peck

[Andy_J]

Hi Pecks,

My problem turned out to be a blocked radiator core, the bottom half of the radiator was blocked. At high speed ther was enogh air being forced thrpough the top of the radiator to cool the car.

Tested it by filling it with boiling water. I fixed it myself by pulling the end taking off the radiator and putting a strip of plastic sown the core to clear it. It is a bit risky as you could end up with a bad seal on the end tanks (so i dont recomend doing this unless you are sure your radiator is the problem). I also removed my water pump to check it, but it was fine in my case

Have you checked you thermostat any air locks, etc in the system. I would suggest you check your radiator is getting hot all the way across, before you check remove water pump.

[PECKHS]

Hi Pecks,

My problem turned out to be a blocked radiator core, the bottom half of the radiator was blocked. At high speed ther was enogh air being forced thrpough the top of the radiator to cool the car.

Tested it by filling it with boiling water. I fixed it myself by pulling the end taking off the radiator and putting a strip of plastic sown the core to clear it. It is a bit risky as you could end up with a bad seal on the end tanks (so i dont recomend doing this unless you are sure your radiator is the problem). I also removed my water pump to check it, but it was fine in my case

Have you checked you thermostat any air locks, etc in the system. I would suggest you check your radiator is getting hot all the way across, before you check remove water pump.

tks andy_j, so it's always one of the usual suspects

i check that out

cheers

[L.G.]

Peck,

As mentioned before water pump is also a possible cause. In my case when idling, temperature wouldn't go down with the fans running at the 3/4 mark. When I raised the revs even slightly it would drop to 2/4 quite fast. It turns out I was running with only 2 of the initial 5 vanes of the pump. It might be worth looking at once you eliminate the easier possiblities, i.e. thermostat.

Good luck,
L.G.