Secondary water pump to cure idle heat up

[lookforjoe]

Got the new programmable timer switch - this one can work with a on/off trigger signal, unlike the Volvo part I had that requires a momentary trigger that I couldn’t work around.

Will be wired thus:

After I get back from Carlisle Import show. Taking the Volvo this year.

Installed the timer today. I had moved (lowered) the sensor so it sat closer to the head. In this location the fan turned on when I came to a halt after highway run, so that is perfect (ambient temp in the 80's today).

Timer circuit makes sure fan will come on after shutdown if thermoswitch (trigger) still indicates over 203ºF. Timer is set to run for about 3min. As long as thermoswitch is grounded (over 203ºF), fan will run. Once thermoswitch drops below temp & circuit opens, fan will run for max 3min (timer circuit) to alleviate heat soak. I can change run time if so required. Had to revise wiring & add diodes to prevent feedback into fusebox, and timer engagement via shared thermoswitch ground circuit.

 

[Dr.Jeff]

As you know a fan draws quite a lot of juice when running, so having it operate for too long after shutdown could kill your battery.

 

[lookforjoe]

As you know a fan draws quite a lot of juice when running, so having it operate for too long after shutdown could kill your battery.

Indeed. That’s why I added the timer . I can also alter the program mode, so it only runs for a short duration regardless of continued bay temp when off. It’s also an efficient fan for its size & only draws 5a at max flow.

 

[Kevin B (Asheville NC)]

True the VAG vehicles' aux pump is primarily to aid the turbo, but they are part of the main cooling system. And the system was designed to allow for the secondary pump to function in conjunction with the primary/main pump. That was the point I was trying to make, having the entire system engineered to work with two pumps so they don't defeat one another. This would be very difficult to do correctly on an existing cooling system not designed around it.

Actually, for the VW's, it was to keep the cylinder head cooled down. Old school Audis only had oil cooled turbos.....

 

[Dr.Jeff]

We must be referring to different models then. It would be interesting to see a schematic for the one you reference, to see how they engineered it for two pumps. Thanks for pointing it out, might offer a method that could be duplicated.

 

[kmead]

As has been found through this discussion, a pump pushing against the back of another pump isn’t going to move more coolant, there needs to be another path that bypasses the existing pump. I have been thinking about a way to use primarily the existing hoses to get around the pump pushing against a pump issue.

Happily in an X there is actually another pathway one could use that puts cooled water right where you want it, into the head.

The idea is this: put a pump at the exit from the radiator using a T with a swing check valve inline after the pump, then run a coolant sized hose back and up into the passenger compartment to a new T added to the heater supply hose behind the heater box. One would want to add a microswitch or other means to create a control system for the pump so it only works at the times you want.

OK so how might this work?

• First when you come to a stop, you would want to turn off the heat on the HVAC system by moving the lever to the right, this ensures flow cannot go through the heater core and right back to the thermostat zone to the back of the existing pump.
• When the pump automatically comes on it pushes the swing gate valve open, allowing cooled coolant to flow back to the existing heater supply hose which leads to the water pump end of the head.
• The coolant will flow through the head, through the thermostat and back to the radiator creating a new path back to the added pump, effectively bypassing the existing pump.
• As the new pump isn’t flowing a huge amount and the existing pump isn’t flowing a huge amount, the line to the radiator hot side will be sufficient for the flow without impinging the flow from the main pump through the block cooling galleries.

One could use an actuated valve instead of the swing check valve to ensure there can be no flow in the ‘wrong’ direction from the heater core supply through the secondary pump (I doubt there would be such an issue but just because you are paranoid doesn’t mean they aren’t watching you).

OK so there is an idea, now do what we do: pick it apart and see how we might improve this idea or show that it is another bit of useless drivel spread across the XWeb by yours truly

 

[Dr.Jeff]

Or maybe when you come to a stop you could just jump out, open the engine lid, and use one of these until the traffic light turns green:

Its the "keep it simple" theory.

 

[kmead]

You missed the stupid part...

I would pay money to see you do that, with that particular fan.

Though, it wouldn’t top the time I went to Vegas for CES and was walking up to the strip when a minivan whips into the parking lot ahead of me, the doors fly open, out jump three guys in suits and two ladies wearing what they were born with (with significant enhancement mind you in a few spots).

The one guy has a camera, the other four run over to the company sign by the entrance and arrange themselves around the sign and a couple of quick flashes and they dash into the van and peel out of there in all of about 30 seconds. Apparently some sort of scavenger hunt.

They don’t do things like that in Grand Rapids...

 

[Dr.Jeff]

Following Karl's idea (not the latest one about Vegas activity), the heater circuit as a whole could be used as a "bypass" coolant path. Connect the existing heater fittings (on the engine) to the secondary pump and install a much larger sized core/cooler (mounted externally) with dedicated fan. This would be more of a auxiliary cooling system than a flow enhancer. It could be temperature controlled to only run when a certain engine temp is reached. But that would eliminate the heater. Hence the extra devices/controls Karl describes <previously> to preserve the heater function.

I think Karl's concept would need to be fully automated to preclude having to manually shut the heater off at stops (if I understood you correctly). It might be getting a bit complicated (ergo the Japanese fan joke above), which could possibly lead to reliability issues? But preserving the use of the heater is a definite plus.

However I'm still not 100% sure how such as bypass circuit would inter play with the main cooling circuit, in terms of pressure/flow differentials. At some point the two circuits must be connected to one another regardless of routing. So the pumps may still compete with one another to some extent.

Looking from a different perspective, have we explored the benefit of adding a oil cooler to see how much it would reduce heat soak and therefore the temp spikes? The oil pump's circulation is also RPM dependent like the water pump, but having a second method to control heat from the other end will definitely help. This will stabilize engine temps and decrease the thermal load on the radiator cooling system, thereby aiding its function also. A temperature controlled fan can be added to the oil cooler to deal with any temp spikes following a heavy drive then stopping. I've always thought oil coolers don't get enough attention on this forum. Especially considering the high volume of discussion around managing engine heat.

 

[autox19]

Agree on the oil cooler. An oil cooler WILL cool down an engine to a point. think about the old air cooled engines. Air cooled porsches had pretty decent sized coolers and 12-16 quarts of oil! Really they should be called air and oil cooled.

Odie

 

[lookforjoe]

I have an oil cooler. It makes no difference to the discussed issue, IMO, as the oil is not considered ‘hot’ ( cooler t/stat doesn’t open until 203f) until it’s over coolant temp - typically a little above 200f.

I like Karl’s idea. What I failed to mention (or just plain forgot about) was that after I tried using the aux water pump to move coolant in the main pathway was that I routed it’s I/O to a large heater core mounted under the front, behind that central jacking point. So, when the pump engaged via the thermoswitch, it pulled coolant out the main circuit, ran it through the core, and pushed it back into the upper hose.

I can’t recall however what the results were. I don’t think I tried using a lower temp sender to engage the pump a little earlier - which is what needs to happen. I also can’t find any pics of the core, just one where it is obvious the hoses are going rearward off the pump. I based it in the premise that turning the heat on always works to drop the coolant temp a notch or two.

EDIT - found a (bad) pic of the core

In other news, the programmed mode I chose for my timer kept the bay fan running in excess of 8min today, as the thermoswitch kept the trigger signal active. Not good, as the ambient temps are not even that high yet- at this rate in the dead of summer the motor would likely retain temp for 10plus min every time I shut it down. Bad for my battery life. I switched to a different function mode that only allows the trigger to activate only once, so the fan will never run after shutdown beyond the prescribed 3min I set.

 

[Dr.Jeff]

cooler t/stat doesn’t open until 203f

It has a lot to do with the climate where I'm located. But I like to have a coolant thermostat at 170F, which keeps actual coolant temps around 180 most of the time. And the oil cooler's fan thermostat around 170-175 (it is adjustable so a little difficult to know the exact temp setting), which again isn't actual oil temp (closer to 190 due to the smaller size of the oil cooler compared to the coolant radiator). And I can tell the oil cooler is cooling the engine by the cycling of its fan.

But the important information is that you have a oil cooler and still experience the temp spikes.

Something I've wondered about is how accurate the coolant temp readings are. I don't mean in terms of gauge accuracy or the sender's signal. But relative to the internal temps around various places within the engine. I've played with a non-contact thermometer and found extremely wide variances from spot to spot all around the entire engine. So depending on where the temp sender is located, actual heat levels may be much different at various times/places. It could be possible that the location of the sender is such that it sees a localized hot spot following hard/prolonged running (a delayed reaction to the extra work load). Meanwhile the majority of the engine does not experience this spike (or at least not nearly as much). But I don't see any way to measure this without a ton of specialized temp monitoring equipment. And it could in fact be the opposite situation.

 

[lookforjoe]

The coolant temp sender is in the main galley that runs front to back on the forward side of the head, so I would say it’s pretty representative of coolant temps overall, VS a possible localized increase.
The gauges can be influenced in their reading by a bad ground in the cluster - when my parking light circuit ground was flaky the gauges would all rise by about 10% when the lights were turned on.

 

[autox19]

The key I had was "too an extent" under normal driving where a car without a oil cooler stays within the normal temperature range, you of course will not notice a difference as the thermostat will keep up. But in extreme conditions it will make a difference. may only be 2-5 degrees, but it does. We tested this back in the 80's where my friend with a celica ITA racer. He dropped on an average 4 degrees during a hot lap session after adding an oil cooler. Still ran hot, but was cooler. he then had a new radiator made that was more efficient to get temps down where he wanted them. Of course he also gained the advantage of the oil staying at the optimum temperature so it didnt separate.
I am not saying that an oil cooler will keep a water cooled engine at the right temperature, I am just indicating it will help. If my swap doesnt start staying cool, I will have my own example to post numbers as currently I am not running an oil cooler.

Odie.

 

[Dr.Jeff]

I agree on both points:

The temp spikes aren't likely to be a factor of the sensor's location. I was quite surprised however at how dramatically the temp varied from one spot to another along the head...even a couple inches here and there. It would be interesting to connect another sender, in another location on the engine, to another gauge, to compare with the stock one (under the same conditions).

An oil cooler will help but only to a degree (no pun intended). On these vehicles, with mid-mounted engines that tend to run hot, I believe it is important to have one regardless. And in some cases it might be enough improvement to make a difference; it would be good to know the oil temp is being kept in check when the engine (coolant) temp spikes. But I think the cooling system is the primary target to be addressed.

On another note. The fact the "exhaust fan" wants to keep running for so long might indicate the fan isn't making that much of a difference in actual temp decrease (things seem to be staying hot even with it running)? Perhaps its location or general air ducting around the bay could improve the fan's effectiveness? Did you notice if it made a significant difference in reducing the temp spikes?

 

[kmead]

There is a lot of mass in the engine, even pulling large quantities of air past it takes a long while to cool it as the surface area isn’t that large relative to the mass you are cooling.

And the fact that the engine exterior isn’t optimized as an object to act as a cooling system doesn’t help

 

[RJH]

For the love of God, MWB really needs to develop a (comparable engine swap) Honda Fit engine swap kit for the X. Really tired of reading story after story of constant multiple engine problems and engine patch jobs. This board more about fixing mechanical problems rather then a site for X1/9 enthusiasts.

 

[Dr.Jeff]

There is a lot of mass in the engine, even pulling large quantities of air past it takes a long while to cool it as the surface area isn’t that large relative to the mass you are cooling.

Very true. It is one of three types of heat transfer. And in this case it is the least effective (lowest efficiency) type.

When you finally decide to solve the issue and convert to one electric coolant pump (replacing the stock pump), consider including a similar timing device that will allow the pump to run on a bit after engine shut down.

Actually that maybe the one situation where having an auxiliary electric pump could offer a little benefit. Having it start running when the engine is shut off (therefore the stock pump is not running) and use a temp/timer control to allow some run on. This will help cool it down without heat soak. But naturally it is only effective when shutting off the engine, so it won't help when you come to a stop light and see a temp spike.

A timer to allow some run on for the rad fan(s) is also a good idea if the cooling system is experiencing problems keeping up with the temp levels (i.e. a cooling system that is insufficiently sized/engineered for the vehicle).

 

[lookforjoe]

For the love of God, MWB really needs to develop a (comparable engine swap) Honda Fit engine swap kit for the X. Really tired of reading story after story of constant multiple engine problems and engine patch jobs. This board more about fixing mechanical problems rather then a site for X1/9 enthusiasts.

If you are an enthusiast, you spend time fixing and improving, it's what you do.

 

[lookforjoe]

On another note. The fact the "exhaust fan" wants to keep running for so long might indicate the fan isn't making that much of a difference in actual temp decrease (things seem to be staying hot even with it running)? Perhaps its location or general air ducting around the bay could improve the fan's effectiveness? Did you notice if it made a significant difference in reducing the temp spikes?

The fan is making a difference. It is keeping the temp from rising above normal while stationary, which is exactly what I wanted it to do.

It kicks on before the radiator fans, which engage when the needle hits the upper edge of the 190º marker. It's also only a 7" 500cfm fan. One could certainly install a larger fan, I don't see the need. As far as the run on, that is a function of both the sensor location and timer delay, which are both adjustable. The only thing I need to tweak is the offset of the sensor from the head to regulate engagement. The run-on timer I can easily change to whatever value I want.